Kosaka, Yuki
Current rating: 1487
Record: 19-20-1
| Grand Prix Chiba 2019 (M20 limited) | starting rating: 1519 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 372 | Shimadu, Naofumi (1533) | Lost 0-2 | -181501 |
| 2sealed | 745 | Matsuda, Tomoya (1484) | Won 2-0 | +181519 |
| 3sealed | 726 | Machida, Takahiro (1723) | Won 2-0 | +211540 |
| 4sealed | 595 | Okino, Ryuu (1650) | Lost 1-2 | -161524 |
| 5sealed | 751 | Kobayashi, Atsumu (1477) | Lost 0-2 | -191505 |
| 6sealed | 685 | Mizuguchi, Tatsuya (1498) | Lost 0-2 | -181487 |
| top | average opponent: 1561record: 2-4 | new rating: 1487 | ||
| Grand Prix Kyoto 2019 (RNA standard) | starting rating: 1519 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 404 | Okamoto, Masahiro4209 (1525) | Lost 0-2 | -181501 |
| 2standard | 544 | Yamamura, Toshiki (1481) | Won 2-1 | +181519 |
| 3standard | 821 | Goto, Kosuke (1421) | Won 2-0 | +161535 |
| 4standard | 543 | Kamiya, Kazuhiro (1543) | Lost 0-2 | -181517 |
| 5standard | 509 | Jin, Tao (1476) | Lost 1-2 | -181499 |
| 6standard | 638 | Morishita, Choryo (1493) | Lost 0-2 | -181481 |
| 7standard | 618 | Takada, Narumasa (1533) | Won 2-1 | +191500 |
| 8standard | 560 | Horie, Hiroshi (1556) | Won 2-0 | +191519 |
| top | average opponent: 1504record: 4-4 | new rating: 1519 | ||
| Grand Prix Chiba 2018 (M19 limited) | starting rating: 1524 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 364 | Murayama, Kyohei (1500) | Won 2-0 | +181542 |
| 2sealed | 103 | Shinohara, Gen 8933 (1525) | Lost 1-2 | -191523 |
| 3sealed | 930 | Usui, Mitsuru (1505) | Lost 0-2 | -181505 |
| 4sealed | 1054 | Hidaka, Takuya (1436) | Won 2-1 | +171522 |
| 5sealed | 720 | Oku, Daisaku (1463) | Lost 0-2 | -191503 |
| 6sealed | 809 | Yamada, Mitsuhiro (1560) | Won 2-1 | +191522 |
| 7sealed | 561 | Otuka, Ryutaro (1407) | Lost 1-2 | -201502 |
| 8sealed | 544 | Kubota, Sin (1490) | Won 2-0 | +171519 |
| top | average opponent: 1486record: 4-4 | new rating: 1519 | ||
| Grand Prix Nagoya 2016 (OGW limited) | starting rating: 1487 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 654 | Ishikawa, Jun (1430) | Won 2-1 | +171504 |
| 2sealed | 489 | Hasegawa, Gaku (1736) | Won 2-1 | +231527 |
| 3sealed | 169 | Sorakup, Aekarash (1677) | Lost 1-2 | -161511 |
| 4sealed | 820 | Ishihama, Yuki (1486) | Lost 1-2 | -181493 |
| 5sealed | 895 | Lee, Rick Hup Beng (1788) | Won 2-1 | +231516 |
| 6sealed | 714 | Shimura, Ichirou (1748) | Won 2-0 | +221538 |
| 7sealed | 321 | Nakayama, Takuya (1713) | Won 2-1 | +211559 |
| 8sealed | 186 | Kitaoka, Takaaki (1604) | Lost 1-2 | -171542 |
| 9sealed | 297 | Ohata, Hiroyuki (1532) | Lost 0-2 | -181524 |
| top | average opponent: 1635record: 5-4 | new rating: 1524 | ||
| Grand Prix Kobe 2015 (BFZ standard) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 265 | Kaji, Kyousuke (1545) | Lost 0-2 | -171483 |
| 2standard | 812 | Sato, Motohiko (1506) | Lost 1-2 | -181465 |
| 3standard | 1070 | Kihara, Yasuyuki (1382) | Won 2-1 | +171482 |
| 4standard | 1151 | Ando, Masanori (1316) | Lost 0-2 | -211461 |
| 5standard | 1079 | Miyazaki, Kazuyuki (1035) | Lost 1-2 | -261435 |
| 6standard | 965 | Hirami, Akihiro (1403) | Won 2-1 | +181453 |
| 7standard | 806 | Yamato, Kohei (1429) | Won 2-0 | +171470 |
| 8standard | 677 | Sakurai, Tomoya (1429) | Won 2-0 | +181488 |
| 9standard | 438 | Yonezaki, Daisuke (1480) | Draw 1-1 | -11487 |
| top | average opponent: 1391record: 4-4-1 | new rating: 1487 | ||