Yamaguti, Koichi
Current rating: 1467
Record: 4-6
| Grand Prix Yokohama 2013 (GTC limited) | starting rating: 1501 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 258 | Fukai, Kazunobu (1463) | Won 2-0 | +171518 |
| 2sealed | 97 | Hidaka, Ayumi (1648) | Lost 0-2 | -161502 |
| 3sealed | 227 | Sakurai, Taiki (1527) | Lost 0-2 | -171485 |
| 4sealed | 414 | Kobayashi, Makoto (1479) | Lost 1-2 | -181467 |
| average opponent: 1529record: 1-3 | new rating: 1467 | |||
| Grand Prix Yokohama 2012 (modern) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1modern | 110 | Toshida, Shin'ichi (1367) | Won 2-1 | +161516 |
| 2modern | 318 | Nagaoka, Takayuki (1849) | Lost 1-2 | -131503 |
| 3modern | 353 | Kobashi, Motoki (1480) | Won 2-0 | +181521 |
| 4modern | 397 | Takahashi, Kazuya (Kanagawa) (1500) | Won 2-0 | +181539 |
| 5modern | 307 | Hase, Shun (1485) | Lost 0-2 | -191520 |
| 6modern | 411 | Satou, Yuuya (1470) | Lost 0-2 | -191501 |
| average opponent: 1525record: 3-3 | new rating: 1501 | |||