People · Japan
Kohei Aruga (有賀康平)
5×5 · top 0.23% of 41,402 all-time · competing since April 2025 · 2025ARUG01
Kohei Aruga (有賀康平) has been competing for a year. His best event is the 5×5: a personal-best single of 40.75, set at Tokai Big Cubes 2025, puts him in the top 0.23% of the 41,402 people who have ever been ranked in the event, and 1st in Japan. Until July 2017, no official 5×5 solve in the world had been that fast. Across 7 competitions since April 2025, he has put 121 official solves on the record across five events. Solve to solve, his 3×3 times vary about 14% around a typical one, an early reading from 6 counted rounds. His 5×5 best has come down from 48.50 in June 2025 to 40.75, a 16% improvement. Kohei has entered seven competitions, more competitions than 88% of everyone who has ever competed.
Standing, event by event
vs everyone ever ranked| Event | PB single | PB average | All-time standing | Japan | |
|---|---|---|---|---|---|
| 5×5 | 40.75 | 48.35 | top 0.23% | 1 / 426 | |
| 7×7 | 2:01.07 | 2:03.04 | top 0.66% | 1 / 188 | |
| 6×6 | 1:22.45 | 1:28.69 | top 0.88% | 2 / 209 | |
| 3×3 | 7.06 | 8.27 | top 1.4% | 64 / 3,360 | |
| 4×4 | 28.65 | 31.64 | top 2.1% | 25 / 679 |
Percentile against all competitors ever ranked in each event, a fairer measure than raw rank, because the pools differ by a factor of ten.
The line so far
Best single per competition, 5×5. Faster is higher — the axis is the right way up.
The story so far
- 12 Apr 2025First competition: Tokai Spring 2025. A 7.06 3×3 single to start from.
Competitions
- Tokai Autumn 2026 · 11 Oct 2026
- Japan Championship 2026 · 18 Jul 2026 — 2 personal bests set
- Tokyo Summer 2026 · 13 Jun 2026 — 1 personal best set
- Tokai Big Cubes 2025 · 14 Dec 2025 — 2 personal bests set
- Tokyo Autumn 2025 · 23 Sep 2025
- Kansai Odd and BLD 2025 · 15 Jun 2025 — 2 personal bests set
- Tokai Spring 2025 · 12 Apr 2025
Reading this page: a single is one solve's time · an average is the middle three of five solves, best and worst discarded · a PB is a personal best · a DNF (did not finish) is an attempt with no valid result: a popped piece, an unsolved face, an over-limit memorisation · top X% compares against everyone ever ranked in that event, which is fairer than raw rank because event pools differ tenfold.
The circuit
The people whose scorecards keep turning up next to his.
- Tomohiro Kobayashi (小林知広) — met in 30 rounds, finished ahead 27 times
- Ivan Li Ka Leong (李嘉亮) — met in 24 rounds, finished ahead once
- Sota Nakamura (中村荘太) — met in 23 rounds, finished ahead 23 times
Next targets
- A sub-40 5×5 single — 73 people have one; it is 0.75 away.
- A sub-2:00 7×7 single — 86 people have one; it is 1.07 away.
Targets move as he improves.