Arita, Koichi
Current rating: 1730 (#4785)
Record: 35-18
| Grand Prix Chiba 2018 (M19 limited) | starting rating: 1796 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 67 | Okumura, Noriaki (1651) | Lost 0-2 | -211775 |
| 2sealed | 788 | Otahara, Sho (1583) | Lost 1-2 | -211754 |
| 3sealed | 1187 | Hakozaki, Yuta (1446) | Lost 1-2 | -241730 |
| top | average opponent: 1560record: 0-3 | new rating: 1730 | ||
| Grand Prix Nagoya 2016 (OGW limited) | starting rating: 1756 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 319 | Tanaka, Shingo (1521) | Won 2-1 | +141770 |
| 2sealed | 457 | Kawakami, Takehito (1593) | Lost 0-2 | -211749 |
| 3sealed | 758 | Kanehara, Masataka (1479) | Won 2-1 | +131762 |
| 4sealed | 798 | Kobayashi, Hideki (1739) | Won 2-0 | +171779 |
| 5sealed | 442 | Nakamura, Hajime (1604) | Lost 1-2 | -211758 |
| 6sealed | 602 | Mizuno, Nobuyoshi (1470) | Lost 0-2 | -231735 |
| 7sealed | 789 | Yanagisawa, Makoto (1421) | Won 2-1 | +131748 |
| 8sealed | 587 | Sato, Yuichi (1444) | Won 2-0 | +121760 |
| 9sealed | 509 | Yasuda, Takaaki (1522) | Won 2-0 | +141774 |
| 10draft | 294 | Matushita, Masakazu (1533) | Won 2-1 | +141788 |
| 11draft | 268 | Oshima, Yuki (1690) | Won 2-0 | +161804 |
| 12draft | 225 | Iwazaki, Yuuta (1639) | Won 2-0 | +151819 |
| 13draft | 27 | Mizumoto, Hirotaka (1529) | Lost 1-2 | -231796 |
| top | average opponent: 1553record: 9-4 | new rating: 1796 | ||
| Grand Prix Shizuoka 2015 (KTK limited) | starting rating: 1746 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 77 | Kokura, Hironori (1500) | Won 2-0 | +141760 |
| 2sealed | 57 | Matsuda, Atsushi (1478) | Won 2-1 | +131773 |
| 3sealed | 200 | Anan, Kazuyoshi (1551) | Won 2-1 | +141787 |
| 4sealed | 60 | Kozakai, Yukio (1725) | Lost 1-2 | -191768 |
| 5sealed | 203 | Aryabhima, Rahman (1743) | Won 2-0 | +171785 |
| 6sealed | 79 | Noguchi, Takeshi (1544) | Lost 1-2 | -221763 |
| 7sealed | 107 | Yamaguchi, Yuuichi (1597) | Won 2-1 | +151778 |
| 8sealed | 133 | Watanabe, Yousuke (1557) | Lost 1-2 | -221756 |
| top | average opponent: 1587record: 5-3 | new rating: 1756 | ||
| Grand Prix Nagoya 2014 (BNG limited) | starting rating: 1582 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 3 | Kawanishi, Naoki (1465) | Won 2-1 | +161598 |
| 2sealed | 84 | Takao, Syunya (1540) | Won 2-1 | +171615 |
| 3sealed | 48 | Hoshi, Koutarou (1503) | Won 2-0 | +161631 |
| 4sealed | 14 | Komatsu, Satoshi (1667) | Won 2-0 | +191650 |
| 5sealed | 3 | Tanahashi, Masayasu (1792) | Won 2-1 | +201670 |
| 6sealed | 9 | Matsui, Hisataka (1804) | Won 2-0 | +211691 |
| 7sealed | 2 | Murata, Toshiaki (1901) | Won 2-1 | +211712 |
| 8sealed | 6 | Shimizu, Yousuke (1671) | Won 2-1 | +181730 |
| 9sealed | 1 | Sei, Makoto (1660) | Won 2-0 | +161746 |
| 10draft | 92 | Sato, Takatoshi (1751) | Lost 1-2 | -181728 |
| 11draft | 22 | Kim, Chang-Hoi (1628) | Won 2-0 | +171745 |
| 12draft | 12 | Kasuga, Ryosuke (1699) | Won 2-1 | +171762 |
| 13draft | 3 | Kawasaki, Keita (1692) | Lost 1-2 | -201742 |
| 14draft | 46 | Ishiwada, Hiroyuki (1702) | Won 2-0 | +181760 |
| 15draft | 9 | Lee, Shi Tian (2010) | Lost 1-2 | -141746 |
| top | average opponent: 1699record: 12-3 | new rating: 1746 | ||
| Grand Prix Yokohama 2013 (GTC limited) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 400 | Shindo, Yoshiya (1496) | Won 2-0 | +181518 |
| 2sealed | 270 | Murao, Masaaki (1482) | Won 2-0 | +171535 |
| 3sealed | 172 | Takeda, Hiroya (1483) | Won 2-1 | +171552 |
| 4sealed | 57 | Shiraishi, Masaharu (1612) | Won 2-1 | +191571 |
| 5sealed | 14 | Syouta, Kubo (1572) | Lost 0-2 | -181553 |
| 6sealed | 68 | Onodera, Yusuke (1560) | Won 2-0 | +191572 |
| 7sealed | 18 | Niimi, Kiyoaki (1681) | Lost 1-2 | -161556 |
| 8sealed | 245 | Kosemura, Tomohiro (1513) | Won 2-1 | +171573 |
| 9sealed | 222 | Sunada, Shougo (1715) | Won 2-1 | +201593 |
| 10sealed | 106 | Murase, Hiroshi (1857) | Lost 1-2 | -131580 |
| 11sealed | 93 | Wada, Hiroya (1605) | Lost 1-2 | -181562 |
| 12draft | 38 | Takao, Akinao (1640) | Won 2-0 | +201582 |
| 13draft | 95 | Sasaki, Yuuichirou (1575) | Won 2-1 | +181600 |
| 14draft | 66 | Itou, Takanori (1622) | Lost 1-2 | -181582 |
| top | average opponent: 1601record: 9-5 | new rating: 1582 | ||