Wisteria/BDEC-01

Also known as Odyssey

Operated by University of Tokyo at University of Tokyo, Kashiwa Campus .

Phase 1 seed dataset, compiled by hand. These rows were built from public operator, laboratory and vendor sources. A mechanical second-reader pass has since fetched every cited source: 1092 of 1153 systems have a readable citation that names them, and 40 are genuinely weakly sourced. Every claim carries its source and a confidence tier. Treat anything below verified as a lead, not a citation.

Measured performance

Rmax: 22.12 PFlop/s
Rpeak: 25.95 PFlop/s
Rmax ÷ Rpeak: 85.2%
Cores: 368,640
Power: 1.47 MW
Per watt: 15.1 GF/W

Figures are as last publicly reported for the configuration described below, not a live measurement. Where a system was upgraded in place, the post-upgrade configuration is shown and the earlier one appears in the timeline.

What this machine is made of

One row per supplier relationship. “Supplier at build” is the company that shipped the part at the time; where that company has since been acquired, the parent it rolls up to today is shown beside it. That distinction is what makes ticker-level aggregation possible across a thirty-year dataset.

Role	Part	Supplier at build	Quantity	Confidence	Source
Integrator	- PRIMEHPC FX1000	Fujitsu 6702TSE	-	Verified	top500.org cc.u-tokyo.ac.jp
CPU	Fujitsu A64FX CPUs Armv8.2-A SVE · 48C · 2.2 GHz · 7 nm A64FX 48C 2.2GHz	Fujitsu 6702TSE	-	Verified	top500.org cc.u-tokyo.ac.jp
Interconnect	Fujitsu Tofu Interconnect D Interconnect 6D mesh/torus · 6.8 GB/s per link per direction Tofu interconnect D	Fujitsu 6702TSE	-	Verified	top500.org cc.u-tokyo.ac.jp
Operating system	Red Hat Enterprise Linux Operating systems Linux distribution · Open source, commercial support subscription Red Hat Enterprise Linux	Red Hat IBMNYSE rolls up to IBM	-	Verified	top500.org cc.u-tokyo.ac.jp

The read

The Odyssey (A64FX, CPU-only simulation) partition of the University of Tokyo's Wisteria/BDEC-01; a separate, much smaller GPU partition called Aquarius exists at the same site but is not TOP500-ranked and is not recorded here. The university's own ITC page independently states 25.9 PFLOPS peak and 368,640 cores, matching TOP500's figures exactly, and confirms the May 2021 launch date; Rmax and power are not independently republished. Sited at the ITC Supercomputing Division's Kashiwa campus, distinct from the university's older, decommissioned Hongo-campus computer centre already recorded for the 1996 `sr2201-tokyo` system.

Timeline

2021-05 First operational source
2023-11 List debut at #55 (November 2023) source

Public list appearances

Pointers only: rank and edition, linking to the canonical entry. We do not reproduce list tables. See sourcing policy.

Site & facility

University of Tokyo, Kashiwa Campus

Location: Kashiwa, Chiba, Japan
Commissioned: 2021

cc.u-tokyo.ac.jp kashiwa.u-tokyo.ac.jp

Change history

2026-09-22 Gained a Green500 rank pointer (#55 on the 2023-11 list)

Source check

We fetched this system's own citations and recorded whether each page actually mentions it. This is a corroboration signal, not a fact check, and it is published so you can see how well the sourcing holds up rather than take it on trust.

Cited source	Result	Found on the page
top500.org	names system and part	Fujitsu A64FX, Fujitsu Tofu Interconnect D
cc.u-tokyo.ac.jp	names system and part	Fujitsu A64FX, Fujitsu Tofu Interconnect D

Checked 2026-10-09 by pnpm verify. Re-run it and the table changes with the web.