Global Fujitsu Distinguished Engineer

Yuichiro Ajima


I am currently working on supercomputer systems development. My technical areas of expertise are system architecture and interconnect. To present, I have been engaged in the development of the Fugaku and the K computer, and the PRIMEHPC series. In the development, I was in charge of the specifications for Fujitsu's Tofu Interconnect.


Developed the system-wide interconnection networks for the K computer and Fugaku, contributing to improving the performance of applications in the broad area of supercomputing. Obtained and holds the essential patent of the interconnect technology. Currently actively presents papers and talks at international conferences, and lectures at universities.

[Awards received]

  • Medal with Purple Ribbon (a type of Japanese Medals of Honor), 2020 (Related Link)open in new window
  • Science and Technology Award (Development Category) Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology, 2017
  • National Commendation for Invention, Imperial Invention Prize, 2014
  • The Ichimura Prize in Industry for Distinguished Achievement, 2012

[TV Appearance]

  • New Project X - Challengers - (2024, June 15). "The Battle of Minds: Engineers Aim for the World's Fastest Supercomputer 'K' ", NHK, Japan.

[Academic conference presentations, lectures, etc.]

  • Japan
    • Ajima, Yuichiro, Motokurumada, Tsuyoshi, Akiya, Sadanori, Odajima, Tetsuya, Yoshikawa, Takahide, and Mizutani, Yasushi (2023, September 26). Initial Study Results and Issue Analysis of Node Architecture for the Next-Generation Computing Infrastructure [Research presentation], Information Processing Society of Japan's 191st HPC Research Seminar, Sendai, Japan.
    • Ajima, Yuichiro, Motokurumada, Tsuyoshi, Akiya, Sadanori, and Mizutani, Yasushi (2023, May 10). Technology Trends Survey and Initial Study of Node Architecture for the Next-Generation Computing Infrastructure [Research presentation], Information Processing Society of Japan's 189th HPC Research Seminar.
    • Ajima, Yuichiro (2023, April 12). Fugaku Supercomputer System Overview and Expectations for Co-Packaged Optics Technology [Lecture]. 6th regular meeting of Co-packaging Optics Study Committee, Tokyo, Japan.
    • Miki, Atsushi & Ajima, Yuichiro (2023, January 27). Predictions and Challenges for Optical Packaging for Achieving Throughput over 100 Tb/s, in the Optical Packaging Technology Roadmap Working Group volume of High-Performance Computing, Optical Packaging Technology Committee, The Japan Institute of Electronics Packaging, pp. 28-36.
    • Ajima, Yuichiro (2022, December 14). Supercomputers and Advanced Packaging Technology [Lecture]. SEMICON Japan 2023 Advanced Packaging and Chiplet Summit, Tokyo, Japan.
    • Ajima, Yuichiro (2022, November 22). Differences and Common Features between Networking Technologies in Supercomputers and Data Centers [Special lecture]. 1st Symposium of Council on Devices and Systems for Next-Generation Green Data Centers, Kawasaki, Japan.
    • Ajima, Yuichiro (2022, June 1). Utilization of Optical Transmission in Top-Level Supercomputers Including "Fugaku" [Invited paper], IEICE Transactions on Electronics, vol. J105-C, no. 6, pp. 200-206.
    • Ajima, Yuichiro (2022, March 15). Trends in Supercomputer Interconnect Technologies Including Tofu Interconnect D in "Fugaku" [Lecture]. 2022 IEICE General Conference, electronics society requested symposium CI-8-1, online.
    • Ajima, Yuichiro (2020, July 20). High-dimensional Interconnect Technology for the K Computer and the Supercomputer Fugaku [Technical Report]. Fujitsu Technical Review.
  • International

Value Creation

These technologies led to the realization of the K computer and Fugaku, which both took the top positions in renowned benchmark rankings. The K computer was the first to ever top each of the TOP500, HPCG, and Graph500 rankings. Fugaku also ranked first in the world for the newly established HPL-AI benchmark (now HPL-MxP), becoming the first supercomputer ever to top 4 rankings. In addition to the contributions of the K computer and Fugaku to society and scientific technology, they also contributed to improved brand awareness as the symbol of Fujitsu's technical prowess.