Milestone-Proposal talk:Sakuma Frequency Converter Station, 1965

Advocates’ Checklist (Read Only; Do Not Edit)

1. Is the proposal for an achievement rather than for a person? If the citation includes a person's name, have the proposers provided the required justification for inclusion of the person's name?
2. Was the proposed achievement a significant advance rather than an incremental improvement to an existing technology?
3. Were there prior or contemporary achievements of a similar nature? If so, have they been properly considered in the background information and in the citation?
4. Has the achievement truly led to a functioning, useful, or marketable technology?
5. Is the proposal adequately supported by significant references (minimum of five) such as patents, contemporary newspaper articles, journal articles, or citations to pages in scholarly books? At least one of the references should be from a peer-reviewed scholarly book or journal article. The full text of the material, not just the references, shall be present. If the supporting texts are copyright-encumbered and cannot be posted on the ETHW for intellectual property reasons, the proposers shall email a copy to the History Center so that it can be forwarded to the Advocate. If the Advocate does not consider the supporting references sufficient, the Advocate may ask the proposer(s) for additional ones.
6. Are the scholarly references sufficiently recent?
7. Does the proposed citation explain why the achievement was successful and impactful?
8. Does the proposed citation include important technical aspects of the achievement?
9. Is the proposed citation readable and understandable by the general public?
10. Will the citation be read correctly in the future by only using past tense? Does the citation wording avoid statements that read accurately only at the time that the proposal is written?
11. Does the proposed plaque site fulfill the requirements as specified by the Milestones Guidelines? (i.e. publicly accessible, appropriately related to the achievement, secure, etc.)
12. Is the proposal quality comparable to that of IEEE publications?
13. Are any scientific and technical units correct (e.g., km, mm, hertz, etc.)? Are acronyms correct and properly upper-cased or lower-cased? Are the letters in any acronym explained in the title or the citation?
14. Are date formats correct as specified in Section 6 of Milestones Program Guidelines? Helpful Hints on Citations, plaque locations
15. Do the year(s) appearing in the citation fall within the range of the year(s) included at the end of the title?
16. Note that it is the Advocate's responsibility to confirm that the independent reviewers have no conflict of interest (e.g., that they do not work for a company or a team involved in the achievement being proposed, that they have not published with the proposer(s), and have not worked on a project related to the funding of the achievement). An example of a way to check for this would be to search reviewers' publications on IEEE Xplore.
17. Are the GPS coordinates correct and in decimal format?
18. Is the proposed achievement controversial because of various reasons including but not limited to: ecological, environmental, social impact, political scandal, etc.? (A relatively simple Google search on the achievement by the advocate, combined with words such as "protest", "scandal", "environmental impact" should be sufficient to alert the advocate.)

Independent Expert Reviewers’ Checklist

1. Is suggested wording of the Plaque Citation accurate?
2. Is evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation?
3. Does proposed milestone represent a significant technical achievement?
4. Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?
5. Have proposers shown a clear benefit to humanity?

In answering the questions above, the History Committee asks that independent expert reviewers apply a similar level of rigor to that used to peer-review an article, or evaluate a research proposal. Some elaboration is desirable. Of course the Committee would welcome any additional observations that you may have regarding this proposal.

Submission and Approval Log (For staff use only)

Submitted date: 21 July 2025
Advocate approval date: 6 August 2025
History Committee approval date:
Board of Directors approval date:

Citation as originally submitted -- Administrator4 (talk) 17:08, 23 July 2025 (UTC)

Sakuma Frequency Converter Station, 1965

The Sakuma Frequency Converter Station, completed in 1965 by Electric Power Development Co., Ltd., enabled the first large-scale power exchange between Japan’s eastern 50 Hz and western 60 Hz grids via a 300 MW motor-generator frequency converter. This achievement addressed a long-standing national frequency division, improving grid reliability, resilience, and laying the foundation for Japan’s future energy interconnection infrastructure.

Expert Reviewer's Report_1_Mukaiyama uploaded by Advocate -- Tomohiro Hase (talk) 13:10, 24 July 2025 (UTC)

Review Report: Sakuma Frequency Converter Station, 1965
Reviewer: Katsumasa Mukaiyama, Tohoku Electric Power Network.
Date: July 24, 2025

(1) Is the suggested wording of the Plaque Citation accurate?

Yes. The proposed citation —

"In 1965, the Sakuma Frequency Converter Station became the world’s first facility to connect power systems operating at different frequencies using a mercury arc rectifier. It enabled the transfer of power between Japan’s eastern 50 Hz and western 60 Hz grids, providing flexibility and stability to the country’s electric power network." —

is accurate and appropriately concise. It clearly describes the technical breakthrough (interconnection via mercury arc rectifier) and its historical and national significance (first in the world, benefits to Japan’s grid).

(2) Is the evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation?

Yes. The proposal provides sufficient and technically accurate evidence, including references [1]–[6], to support the claim that the Sakuma Frequency Converter Station was the world’s first facility of its kind. Notably, Reference [3] (H. Honda, "Construction of Sakuma Frequency Converter Station," JEC, 1965) details the design, implementation, and operational principles of the system. The proposal also includes clear historical documentation of Japan’s east–west frequency divide and the technical approach chosen to bridge it.

(3) Does the proposed milestone represent a significant technical achievement?

Yes. The Sakuma facility represents a globally significant milestone in power systems engineering. As stated in the "Historical Significance" section, it was "the world’s first frequency converter station employing three 100 MVA synchronous machines operating at 275 kV."

(4) Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?

Yes. The proposers adequately mention European HVDC systems and other similar technologies, and clearly differentiate Sakuma’s uniqueness. The section “Features Setting This Work Apart from Similar Achievements” discusses other early frequency conversion attempts, including mercury arc converter systems in Europe. However, Sakuma was the first to apply high-voltage synchronous machines for such a purpose at scale. This method provided operational advantages such as reactive power support, higher efficiency, and long-term reliability. The proposal effectively demonstrates that no comparable facility of this capacity and approach existed at the time.

(5) Have the proposers shown a clear benefit to humanity?

Yes. The Sakuma Converter Station significantly improved the stability and flexibility of Japan’s power system, which remains split into 50 Hz and 60 Hz regions. This facility enabled mutual power support between regions during peak loads and emergencies, including earthquakes and natural disasters, thereby enhancing national resilience. The design became a model for subsequent frequency converter installations worldwide. In this sense, the milestone reflects both an enhancement of national infrastructure and a broader influence on global engineering practices.

Conclusion
The Sakuma Frequency Converter Station of 1965 is a pioneering achievement in electrical engineering. It represents the first successful implementation of a mercury arc rectifier to interconnect asynchronous power grids. The technology addressed a critical infrastructure challenge in Japan and has had a lasting influence on global grid interconnection methods. Given its technical innovation, historical importance, and continued operational legacy, I strongly recommend this proposal for designation as an IEEE Milestone.

[Advocate's Remarks] Mr. Mukaiyama is an expert engineer at the Tohoku Electric Power Network.

Expert Reviewer's Report_2_Taoka uploaded by Advocate -- Tomohiro Hase (talk) 01:20, 27 July 2025 (UTC)

Dear Professor Hase,

I will send my review report you requested.
Please find it below:

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Review Report: IEEE Milestone Proposal – Sakuma Frequency Converter Station, 1965

To: IEEE History Committee
From: Hisao Taoka / Reviewer
Date: July 27, 2025
Subject: Review of Milestone Proposal: Sakuma Frequency Converter Station, 1965 (Docket #: 2025-18)

I have reviewed the proposal for the Sakuma Frequency Converter Station, 1965, to be designated as an IEEE Milestone. My assessment, based on the provided documentation, is as follows:

(1) Is the suggested wording of the Plaque Citation accurate?

Yes, the suggested wording of the Plaque Citation is accurate and effectively summarizes the achievement and its significance. The citation states:
"The Sakuma Frequency Converter Station, completed in 1965 by Electric Power Development Co., Ltd., enabled the first large-scale power exchange between Japan's eastern 50 Hz and western 60 Hz grids via a 300 MW mercury arc rectifier-based frequency converter. This achievement addressed a long-standing national frequency division, improving grid reliability, resilience, and laying the foundation for Japan's future energy interconnection infrastructure."
This aligns perfectly with the proposal's abstract, which describes it as "Japan's first large-scale facility to connect the country's eastern 50 Hz power grid with the western 60 Hz grid" using a "mercury arc rectifier-based frequency converter."

(2) Is the evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation?

Yes, the evidence presented in the proposal is of sufficient substance and accuracy to support the Plaque Citation. The “Social and Historical Significance” section thoroughly details the historical context of Japan's dual-frequency grid, the immediate technical and operational benefits derived from the Sakuma station, and its long-term impact on the nation's energy infrastructure.
Specifically, Reference [1], Susumu Kuwahara; "Sakuma Frequency Converter Station," Vol. 85, No. 925, pp. 1625–1634, The Journal of the Institute of Electrical Engineers of Japan, 1965, provides contemporary and scholarly confirmation of the station's purpose, capacity (300 MW), and operational timeline (completed November 1965).
Furthermore, Figure 2, illustrating "Power Interchange 50 Hz/60 Hz in 1965–1983," visually substantiates the claim of large-scale power exchange. The detailed descriptions in the "Technical Design and Innovation" and "Obstacles" sections further bolster the proposal’s claims with concrete technical details and challenges overcome.

(3) Does the proposed milestone represent a significant technical achievement?

Yes, the proposed milestone represents a highly significant technical achievement. The Sakuma Frequency Converter Station, commissioned in 1965, was a pioneering solution to Japan's unique national frequency divide. At its inception, it was "the largest mercury arc rectifier-based frequency converter in the world."
This frequency conversion system demanded advanced engineering to ensure torsional stability, cooling, noise suppression, and control. Key technical innovations included precision excitation control systems for voltage regulation, acoustic insulation for community compatibility, and custom-designed shafts and bearings to withstand continuous mechanical stress at a utility scale.
The successful design and implementation of such a high-capacity, mechanically coupled system for asynchronous grid interconnection—especially given the lack of precedent in Japan for transferring hundreds of megawatts—marks a profound technical accomplishment.

(4) Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?

Yes, the proposers have adequately described similar achievements and clearly articulated what sets the Sakuma Frequency Converter Station apart. The “What Features Set This Work Apart from Similar Achievements?” section provides a concise comparison with European HVDC systems (e.g., NorNed, BritNed) and North American asynchronous ties (e.g., Miles City HVDC Tie, Rapid City DC Tie).
The proposal correctly highlights that, while these systems utilize HVDC for inter-country energy trade or inter-regional asynchronous ties, they do not address a fundamental frequency mismatch within a single industrialized nation—as was the case in Japan.
The proposal emphasizes that "Japan is the only industrialized nation with two commercial grid frequencies within one country," necessitating a unique solution like Sakuma. Furthermore, the proposal uniquely positions Sakuma by detailing its electronic technological evolution, starting with mercury arc rectifier-based generator sets and later transitioning to a solid-state HVDC back-to-back system in 1993, making it one of the few sites globally to operate under both paradigms of frequency conversion.
This comprehensive comparison effectively demonstrates the distinctiveness and national importance of the Sakuma achievement.

(5) Have the proposers shown a clear benefit to humanity?

Yes, the proposers have shown a clear and substantial benefit to humanity. The Sakuma Frequency Converter Station provided a critical solution to a “serious bottleneck” in Japan's power distribution by enabling “meaningful and stable power interchange between the regions for the first time.”
This significantly enhanced grid flexibility and reliability, leading to tangible benefits such as reducing the need for regional reserve capacity, improving frequency stability, and enabling mutual emergency support—particularly in times of natural disaster, such as earthquakes or typhoons.
The proposal cites simulations from the 1960s showing that Sakuma could reduce frequency drops during outages (e.g., a 0.8 Hz drop reduced to 0.4 Hz for a 340 MW loss in Tokyo), directly contributing to a more resilient and responsive national power grid.
Its continued operation, especially during emergencies like the 2011 Great East Japan Earthquake—where "west-to-east energy transfer proved vital"—underscores its enduring humanitarian impact on energy security and disaster preparedness for the Japanese populace.

Conclusion:
The Sakuma Frequency Converter Station represents an exceptional technical and historical asset. Its pioneering role in bridging Japan's unique dual-frequency power grids, its innovative frequency conversion technology at an unprecedented scale, and its lasting impact on national energy security and grid resilience make it an outstanding candidate for recognition. The proposal is well-supported with compelling evidence and clearly articulates the achievement's significance and distinctiveness.
Therefore, I strongly recommend that the Sakuma Frequency Converter Station be designated as an IEEE Milestone.

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Best Wishes,
Hisao Taoka, Former Professor of Fukui University, IEEE Life Fellow, CIGRE Distinguished Member

Hisao Taoka, Ph. D Engineering Advisor, Power System Solutions Group, Rikei Corporation
Invited Researcher, Energy Network Research Team, Fukushima Renewable Energy Institute, The National Institute of Advanced Industrial Science and Technology (AIST)

[Advocate's remarks_1] Dr. Hisao Taoka is an IEEE Fellow in 2014 for contributions to computing technology for power system analysis and control.

[Advocate's remarks_2] CIGRE is a collaborative global community committed to the world's leading knowledge development program for the creation and sharing of power system expertise. https://www.cigre.org/

Expert Reviewer's Report_3_Nguyen-Van uploaded by Advocate -- Tomohiro Hase (talk) 20:17, 27 July 2025 (UTC)

Dear Prof. Hase,

Please find my review for the Milestone-Proposal: "Sakuma Frequency Converter Station, 1965" below.

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(1) Plaque Citation Accuracy

Yes. The proposed plaque citation is accurate and succinctly captures the essence of the achievement. It correctly identifies the Sakuma Frequency Converter Station as Japan’s first large-scale AC-to-AC interconnection facility, which enabled real-time power exchange between the 50 Hz and 60 Hz grids.

(2) Supporting Evidence for Plaque Citation

Yes. The proposal presents substantial and well-documented evidence supporting the citation. The “Technical Design and Innovation” section outlines the station’s architecture, including its use of mercury arc rectifier sets and its 300 MW capacity. The “Social and Historical Significance” section provides relevant context by explaining the origin of Japan’s dual-frequency grid and the societal need for interconnection.

(3) Significance of Technical Achievement

Yes. The Sakuma Frequency Converter Station represents a landmark technical achievement. It was the first facility in Japan to enable large-scale, bidirectional power exchange between two asynchronous grids. Its use of mercury arc rectifiers and its rapid response capability (300 MW within one second) demonstrated advanced engineering and operational reliability. The station laid the foundation for subsequent interconnection projects, such as the Shin-Shinano and Higashi-Shimizu stations.

(4) Similar or Competing Achievements

Yes. The proposal acknowledges later developments, including the Shin-Shinano and Higashi-Shimizu stations, and distinguishes Sakuma’s mechanical AC-to-AC conversion method from HVDC-based systems. While comparable facilities existed internationally, Sakuma holds particular significance due to Japan’s unique grid structure. Despite Japan’s relatively small geographic area, the creation of a frequency converter station to interconnect asynchronous grids was crucial for optimizing the national energy infrastructure. The Sakuma station addressed this challenge by adapting and enhancing global technologies, fostering domestic innovation. Its successful implementation exemplified both technical ingenuity and international collaboration.

(5) Benefit to Humanity

Yes. The Sakuma station has provided lasting societal benefits. It enhanced grid stability, enabled nationwide load balancing, and strengthened disaster resilience—most notably during the 2011 Great East Japan Earthquake. By facilitating efficient energy distribution, it contributed to Japan’s postwar recovery and sustained economic growth. Its continued operation is a testament to its enduring value and engineering excellence.

Conclusion
The Sakuma Frequency Converter Station is a historically and technically significant achievement. It bridged a century-old infrastructural divide and enabled Japan to operate a more unified and resilient power system. Given its pioneering role, long-term impact, and continued relevance, I strongly support its recognition as an IEEE Milestone.

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Sincerely,

Triet Nguyen-Van, Ph. D.
Control and Power Systems Lab., Department of Intelligent Interaction Technologies, University of Tsukuba

Appreciation of Submitted Reviews -- Zephyrus00jp (talk) 23:26, 28 July 2025 (UTC)

Hello,

This is Chiaki Ishikawa, one of the proposers.
I would like to thank the reviewers for the reviewes posted here in the last few days.
We will study the reviews and see if there are places where we can improve the proposal.
Thank you again for talking the time to read and write the reviews.

Sincerely,
Chiaki Ishikawa

Expert Reviewer's Report_4_Nagao uploaded by Advocate -- Tomohiro Hase (talk) 01:40, 1 August 2025 (UTC)

Here is an expert review report from prof. Nagao

Media:Review Report_Nagao_V2.pdf

[Advocate's remarks] Dr. Masayuki NAGAO
Emeritus Professor, Toyohashi University of Technology, JAPAN
CIGRE Distinguished Member

Expert Reviewer's Report_5_Hashizume uploaded by Advocate -- Tomohiro Hase (talk) 15:39, 6 August 2025 (UTC)

I received the following Expert Review Report from Professor Hiromichi Hashizume, the National Institution for Academic Degrees and Quality Enhancement of Higher Education.　

(Review Report from Prof. Hashizume) *****************************************

Review Report for IEEE Milestone Proposal: Sakuma Frequency Converter Station, 1965

(1) Is the suggested wording of the Plaque Citation accurate?

Yes, the suggested plaque citation is accurate. The wording concisely summarizes the milestone: the Sakuma Frequency Converter Station, commissioned in 1965, as the world’s first frequency converter for nation-wide power grids, enabled direct interconnection between Japan’s eastern (50 Hz) and western (60 Hz) grids for the first time in history, using pioneering high-voltage, direct current (HVDC) conversion technology based on mercury-arc rectifiers. The station’s original capacity was 300MW, which was almost equivalent to a large hydroelectric power plant. The technical accuracy and relevance of all details are precise and reflect the project's actual historical contributions.

(2) Is evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation?

Yes, ample and credible evidence is provided in the proposal.

(a) The Historical Significance section details how the Sakuma Frequency Converter Station facilitated the interconnection of Japan’s two major power grids, previously separated due to differing frequencies, by using HVDC technology [1], [a].

[a] Hiroshi Suzuki: “Comprehensive Survey on the History of Power Systems and Power System Technologies in Japan”, Systematic Survey Report on Technology by the National Museum of Nature and Science, Vol. 29, 2020. March.

(b) The HVDC technology was already known at the time, but it was used for long-range power distributions. The Sakuma FC was the first application of the technology for frequency conversion; however, the HVDC range was only within the premises.

(c) References to contemporaneous technical literature and historical documents (including Japanese-language sources and international engineering journals) corroborate the world-first nature of this installation and the significance of technology transfer and local engineering in the station’s realization [1].

(d) Detailed explanations of the technical composition and subsequent upgrades (from mercury-arc rectifiers to thyristor converters) are well-supported by primary documentation and post-installation operational records [a].

(3) Does the proposed milestone represent a significant technical achievement?

Yes, the Sakuma Frequency Converter Station represents a globally significant technical achievement:

(a) It was the world’s first commercial frequency converter facility for interconnected power systems at grid scale, using HVDC back-to-back link methods to enable direct power exchange between different frequency grids [1].

(b) Its construction solved a unique challenge in Japan, where two major regions used entirely different grid frequencies (50 Hz and 60 Hz), and underscored the importance of such facilities in systems where grid unification is impractical.

(c) The Sakuma project pioneered the introduction and adaptation of HVDC conversion technology, later serving as a testbed for further Japanese development of converter and control technologies, such as the transition from imported mercury arc rectifiers to domestically developed thyristor converters.

(d) The operational successes and experience at Sakuma directly enabled subsequent HVDC and frequency conversion projects in Japan (e.g., Shin-Shinano, Kitahon Interconnection), expanding the utility and resilience of the national grid.

(e) This facility is still maintained using newer technologies to connect the different frequency zones.

(4) Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?

Yes, the context of similar or competing achievements is addressed:

(a) Prior to Sakuma, HVDC transmission technology was at an early stage globally, with experimental installations (such as the 1954 Gotland project in Sweden) but not at grid interconnection scale nor for frequency conversion between asynchronous national networks.

(b) The proposal clearly distinguishes Sakuma as the first commercial application of frequency conversion to connect two large, different frequency grids, highlighting that other technologies and facilities (e.g., rotary converters, early HVDC projects) lacked the scale, operational importance, and technical innovation found at Sakuma.

(c) The relationship between Sakuma’s achievement and subsequent advances in HVDC and frequency conversion is well-documented, ensuring the uniqueness and foundational impact of the milestone are clear.

(5) Have proposers shown a clear benefit to humanity?

Yes, the proposal articulates clear and demonstrable benefits:

(a) The Sakuma Frequency Converter Station has substantially increased the reliability, efficiency, and operational flexibility of Japan’s national grid, allowing for power balancing and support between east and west, especially during emergencies, disasters, or imbalances in supply and demand.

(b) Its role was critical during periods of national rapid economic growth as well as in disaster response, such as after the Great East Japan Earthquake, by enabling large-scale mutual support between grids.

(c) As a true infrastructure milestone, the station’s legacy endures through enhanced grid resilience, fostering technological advancement, and serving as a model for subsequent frequency converter installations worldwide.

Conclusion:
The Sakuma Frequency Converter Station stands as a uniquely valuable technical and historical asset. Its implementation marked a world-first in commercial frequency conversion at the grid level, directly shaping the evolution, resilience, and interconnectedness of modern power systems. The submitted proposal is technically robust, historically well-documented, and fully meets IEEE Milestone standards. I strongly recommend the Sakuma Frequency Converter Station for recognition as an IEEE Milestone.

[Advocate's remarks] Dr. Hashizume is now a special appointed professor, at Research Department of the National Institution for Academic Degrees and Quality Enhancement of Higher Education (NIAD-QE).

Advocate’s Recommendation -- Tomohiro Hase (talk) 15:47, 6 August 2025 (UTC)

Advocate's Recommendation for the IEEE Milestone #2025-18 “Sakuma Frequency Converter Station, 1965”

August 6, 2025

Dear IEEE History Committee,

I am honored to be an advocate for the Milestone Proposal #2025-18, “Sakuma Frequency Converter Station, 1965”.

URL to Proposal:
https://ieeemilestones.ethw.org/Milestone-Proposal:Sakuma_Frequency_Converter_Station,_1965

(1) Review:

I invited five independent experts in the field to conduct a detailed technical review of the proposal. I asked the expert reviewers the following five questions:

Q1: Is the suggested wording of the Plaque Citation accurate?

Q2: Is the evidence presented in the proposal of sufficient substance and accuracy to support the Citation?

Q3: Does the proposed milestone represent a significant technical achievement?

Q4: Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?

Q5: Have the proposers shown a clear benefit to humanity?

I have uploaded the five expert reviewers’ reports to the ETHW website at the following URL to expert reviewer’s reports:
https://ieeemilestones.ethw.org/Milestone-Proposal_talk:Sakuma_Frequency_Converter_Station,_1965

Based on my reading of the five expert reviewer reports, I have received positive ratings from all, indicating their agreement with the proposal's appropriateness for the Milestone.

(2) Advocate’s Checklist:

Below is my checklist with responses:

1. Is the proposal for an achievement rather than for a person? If the citation includes a person's name, have the proposers provided the required justification for inclusion of the person's name? <Yes>

2. Was the proposed achievement a significant advance rather than an incremental improvement to existing technology? <Yes>

3. Were there prior or contemporary achievements of a similar nature? If so, have they been properly considered in the background information and the citation? <Yes>

4. Has the achievement truly led to a functioning, useful, or marketable technology? <Yes>

5. Is the proposal adequately supported by significant references (minimum of five) such as patents, contemporary newspaper articles, journal articles, or citations to pages in scholarly books? At least one reference should be from a peer-reviewed scholarly book or journal article. The full text of the material, not just the references, must be present. If the supporting texts are copyright-encumbered and cannot be posted on the ETHW for intellectual property reasons, the proposers shall email a copy to the History Center so it can be forwarded to the Advocate. If the Advocate does not consider the supporting references sufficient, the Advocate may ask the proposer(s) for additional ones. <Yes>

6. Are the scholarly references sufficiently recent? <Yes>

7. Does the proposed citation explain why the achievement was successful and impactful? <Yes>

8. Does the proposed citation include important technical aspects of the achievement? <Yes>

9. Is the proposed citation readable and understandable by the general public? <Yes>

10. Will the citation be read correctly in the future by only using past tense? Does the citation wording avoid statements that read accurately only at the time the proposal is written? <Yes>

11. Does the proposed plaque site fulfill the requirements? <Yes>

12. Is the proposal quality comparable to that of IEEE publications? <Yes>

13. Are any scientific and technical units correct (e.g., km, mm, hertz, etc.)? Are acronyms correct and properly upper-cased or lower-cased? Are the letters in any acronym explained in the title or the citation? <Yes>

14. Are date formats correct as specified in Section 6 of Milestones Program Guidelines? Helpful Hints on Citations, plaque locations. <Yes>

15. Do the year(s) appearing in the citation fall within the range of the year(s) included at the end of the title? <Yes>

16. Note that it is the Advocate's responsibility to confirm that the independent reviewers have no conflict of interest (e.g., that they do not work for a company or a team involved in the achievement being proposed, that they have not published with the proposer(s), and have not worked on a project related to the funding of the achievement). An example of a way to check for this would be to search reviewers' publications on IEEE Xplore. <Yes>

(3) Advocate’s Comment and Conclusion:

I received satisfactory peer review results from five experts in the field. Their reports and discussions were very useful for my decision as an advocate for Milestone #2025-18 “Sakuma Frequency Converter Station, 1965”.

1. Citation:

The five expert reviewers confirmed the citation’s accuracy and that the contents are supported by evidence, as judged by their responses to questions Q1 and Q2. As an advocate, I share the same judgment as the reviewers.

2. Technical Significance and Historical Value:

The five expert reviewers provided detailed reviews of questions Q3 and Q4. They acknowledged the historical significance. As an advocate, I share their judgment.

3. Benefit to Humanity:

All five expert reviewers provided positive comments, as judged by their responses to question Q5. I concur with their judgment.

4. Advocate’s Conclusion:

All five expert reviewers strongly recognized and supported the proposal, deeming it worthy of the IEEE Milestone recognition. After careful consideration of both the proposal and the expert reviewers’ reports, I strongly recommend the proposal, #2025-18 “Sakuma Frequency Converter Station, 1965”, for the IEEE Milestone.

Best regards,

Dr. Tomohiro Hase, IEEE Fellow
Advocate for Milestone #2025-18, IEEE History Committee

Appreciation of two additional reviews. -- Zephyrus00jp (talk) 01:12, 7 August 2025 (UTC)

Hello, this is Chiaki Ishikawa, one of the submitters.

I became aware of the two additional reviews posted here.

I would like to thank the reviewers for taking the time to read the application and produce the reviews.

I will take a look at the new reviews and see if there are places where I can improve the description. etc. Professor Hashizume's review includes a new reference, and so I will study it and quote it in an appropriate manner in the submission.

Thank you again.

Chiaki Ishikawa, one of the submitters.