Koga, Tokuhiko
Current rating: 1405
Record: 6-11
| Grand Prix Yokohama 2019 (modern) | starting rating: 1477 | |||
| round | table | opponent (rating) | result | Δrating |
| 1modern | 609 | Saka, Yusuke (1490) | Lost 0-2 | -181459 |
| 2modern | 945 | Hatta, Yuusuke (1481) | Lost 0-2 | -181441 |
| 3modern | 1143 | Fujieda, Taira (1384) | Won 2-0 | +171458 |
| 4modern | 985 | Nishinomiya, Takumi (1483) | Lost 0-2 | -171441 |
| 5modern | 998 | Ito, Yoshihiro (1486) | Lost 1-2 | -171424 |
| 6modern | 961 | Masaki, Dai (1407) | Lost 1-2 | -191405 |
| 7modern | 835 | Kawaharada, Kosaku (1378) | Won 2-1 | +181423 |
| 8modern | 693 | Matsumoto, Amiru (1442) | Lost 0-2 | -181405 |
| average opponent: 1444record: 2-6 | new rating: 1405 | |||
| Grand Prix Kobe 2017 (modern) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1modern | 497 | Ochi, Takushi (1439) | Won 2-0 | +171517 |
| 2modern | 529 | Kamiyama, Daiki (1484) | Won 2-0 | +171534 |
| 3modern | 90 | Shimazu, Yoshiki (1644) | Lost 0-2 | -161518 |
| 4modern | 855 | Takahashi, Eiji (1545) | Lost 0-2 | -171501 |
| 5modern | 796 | Kazumasa, Nakamoto (1504) | Won 2-1 | +181519 |
| 6modern | 502 | Kishita, Kengo (1436) | Lost 1-2 | -201499 |
| 7modern | 797 | Ara, Genta (1435) | Won 2-1 | +171516 |
| 8modern | 716 | Yoshida, Shohei (1439) | Lost 1-2 | -191497 |
| 9modern | 647 | Arisue, Kei (1390) | Lost 1-2 | -201477 |
| average opponent: 1480record: 4-5 | new rating: 1477 | |||