Koiwai, Seiko
Current rating: 1393
Record: 0-6
| Grand Prix Yokohama 2019 (modern) | starting rating: 1410 | |||
| round | table | opponent (rating) | result | Δrating |
| 1modern | 475 | Katagiri, Kensuke (1500) | Lost 0-2 | -171393 |
| record: 0-1 | new rating: 1393 | |||
| Grand Prix Shizuoka 2017 (AER standard) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 690 | Nakamura, Fumitake (1526) | Lost 1-2 | -181482 |
| 2standard | 740 | Okuno, Yuuki (1561) | Lost 0-2 | -161466 |
| 3standard | 1208 | Nishimura, Shinji (1468) | Lost 0-1 | -181448 |
| 4standard | 1233 | Kobayashi, Satoru (1393) | Lost 0-2 | -191429 |
| 5standard | 1252 | Naka, Hidehiro (1355) | Lost 0-2 | -191410 |
| average opponent: 1460record: 0-5 | new rating: 1410 | |||