USCF player statistics
Ko, Derek Diaz
Official US Chess recordRegular rating
Published rating · Sep 2026 · 10 published updates since Dec 2025
Other formats against Regular
-52 Quick vs Regular
No national baseline for this rating band yet.
How this rating moves
Between consecutive published observations, provisional included.
- Biggest gain
- +215
- Apr 2026 to May 2026
- Biggest drop
- -44
- Feb 2026 to Mar 2026
- Longest rise
- 1 update
- +215 from Apr 2026 to May 2026
- Current run
- 4 updates
- Unchanged since May 2026
- Typical move
- ±29
- Mean absolute change; spread ±74.9
Regular rating in context
United States
#23,933of 83,635 rated members · higher than 71.3%
59,672 lower · 31 same rating · 23,932 higher · ties share a rank
California
#2,832of 9,051 rated members · higher than 68.6%
6,213 lower · 7 same rating · 2,831 higher · ties share a rank
Where this rating sits · United States
83,635 rated members in 50-point bands · median 800–849 · 6,988 within 100 points of 1,301 (this player included)
1,300–1,349: 1,775 members (2.1%) · highlighted band is the player’s · dashed line is the target
73.2% below 1,350 (61,297 of 83,635; 71.3% below 1,301)
How these comparisons are calculated
Chess67 calculations from the Sep 2026 monthly rating update, using the same population as the USCF statistics pages: US members classified as active in the published monthly records, excluding lifetime-coded records, provisional ratings included. Ties share a rank; “lower” is strictly lower; national and state groups overlap. The target explorer keeps the population fixed, with this player at their recorded rating: it is a rating comparison, not a prediction of future rank.
Published ratings by month
P marks a provisional rating; the small figure is the change since the previous published observation.
| Month | Regular | Quick |
|---|---|---|
| Sep 2026 | 1,301no change | 1,249no change |
| Aug 2026 | 1,301no change | 1,249no change |
| Jul 2026 | 1,301no change | 1,249no change |
| Jun 2026 | 1,301no change | 1,249no change |
| May 2026 | 1,301+215 | 1,249+208 |
| Apr 2026 | 1,086 Pno change · 21 games | 1,041 Pno change · 21 games |
| Mar 2026 | 1,086 P-44 · 21 games | 1,041 P-45 · 21 games |
| Feb 2026 | 1,130 Pno change · 21 games | 1,086 Pno change · 21 games |
| Jan 2026 | 1,130 Pno change · 16 games | 1,086 Pno change · 16 games |
| Dec 2025 | 1,130 P16 games | 1,086 P16 games |