People · Japan
Chihi Koo
3×3 · top 4.1% of 284,439 all-time · competing since April 2023 · 2023KOOC02
Chihi Koo has been competing for 3 years. His best event is the 3×3: a personal-best single of 8.65, set at Bay Area Speedcubin' 63 - Atherton 2024, puts him in the top 4.1% of the 284,439 people who have ever been ranked in the event, and 172nd in Japan. Until July 2008, no official 3×3 solve in the world had been that fast. Across 7 competitions since April 2023, he has put 123 official solves on the record across four events. Solve to solve, his 3×3 times vary about 15% around a typical one; 87% of the 35,811 competitors with ten or more counted rounds hold a tighter spread. His 3×3 best has come down from 15.95 in April 2023 to 8.65, a 46% improvement. Chihi 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 | |
|---|---|---|---|---|---|
| 3×3 | 8.65 | 9.86 | top 4.1% | 172 / 3,329 | |
| 2×2 | 2.26 | 3.87 | top 6.7% | 87 / 1,021 | |
| 3×3 one-handed | 19.63 | 22.06 | top 19.5% | 165 / 529 | |
| Pyraminx | 12.44 | 15.03 | top 69.9% | 555 / 688 |
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, 3×3. Faster is higher — the axis is the right way up.
The story so far
- 27 Apr 2024First sub-10 3×3: 9.18 at Bay Area Speedcubin' 61 - San Jose 2024.
- 25 Jun 2023First sub-15 3×3: 14.96 at Bay Area Speedcubin' 48 - 6.25 Berkeley 2023.
- 1 Apr 2023First competition: Bay Area Speedcubin' 43 2023. A 16.43 3×3 single to start from.
Competitions
- Berkeley Spring 2026 · 26 Apr 2026 — 1 personal best set
- Bay Area Side Events Day 2025 · 23 Feb 2025
- Bay Area Speedcubin' 63 - Atherton 2024 · 22 Jun 2024 — 2 personal bests set
- Bay Area Speedcubin' 61 - San Jose 2024 · 27 Apr 2024 — 2 personal bests set
- Bay Area Speedcubin' 52 - Belmont 2023 · 1 Oct 2023 — 2 personal bests set
- Bay Area Speedcubin' 48 - 6.25 Berkeley 2023 · 25 Jun 2023 — 1 personal best set
- Bay Area Speedcubin' 43 2023 · 1 Apr 2023 — 1 personal best set
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.
- Jonathan Rutenberg — met in 24 rounds, finished ahead twice
- Stanley Tran — met in 23 rounds, never finished ahead
- Zerui Cheng (程泽睿) — met in 22 rounds, finished ahead twice
Next targets
- A sub-8 3×3 single — 7,931 people have one; it is 0.65 away.
- A sub-2 2×2 single — 8,848 people have one; it is 0.26 away.
Targets move as he improves.