Koizumi, Hiroki
Current rating: 1464
Record: 31-34
| Grand Prix Yokohama 2019 (modern) | starting rating: 1468 | |||
| round | table | opponent (rating) | result | Δrating |
| 1modern | 29 | Okuhira, Yoshihisa (1475) | Lost 0-2 | -171451 |
| 2modern | 823 | Nakamura, Ryotaro (1448) | Lost 1-2 | -181433 |
| 3modern | 1068 | Kato, Tomonori (1286) | Won 2-0 | +151448 |
| 4modern | 960 | Echikawa, Yusuke (1461) | Won 2-0 | +181466 |
| 5modern | 745 | Harada, Akio (1544) | Won 2-1 | +201486 |
| 6modern | 612 | Zhang, Qihan (1445) | Lost 1-2 | -191467 |
| 7modern | 721 | Tanaka, Makoto1460 (1354) | Won 2-1 | +161483 |
| 8modern | 430 | Ishii, Asuha (1418) | Lost 0-2 | -191464 |
| top | average opponent: 1429record: 4-4 | new rating: 1464 | ||
| Grand Prix Shizuoka 2018 (standard) (GRN standard) | starting rating: 1419 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 376 | Kubota, Muneaki (1721) | Lost 0-2 | -121407 |
| 2standard | 833 | Moriya, Taiki (1426) | Lost 0-2 | -181389 |
| 3standard | 1030 | Oohashi, Yoshihiro (1463) | Lost 0-2 | -171372 |
| 4standard | 1057 | Ohno, Yohei (1445) | Won 2-0 | +201392 |
| 5standard | 997 | Nakajima, Shunichi (1444) | Won 2-0 | +191411 |
| 6standard | 849 | Ota, Kosuke (1481) | Won 2-0 | +191430 |
| 7standard | 690 | Kimonji, Hiroki (1495) | Won 2-0 | +191449 |
| 8standard | 521 | Tamari, Toshiya (1520) | Won 2-1 | +191468 |
| top | average opponent: 1499record: 5-3 | new rating: 1468 | ||
| Grand Prix Kobe 2015 (BFZ standard) | starting rating: 1464 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 447 | Azechi, Akira (1500) | Won 2-0 | +181482 |
| 2standard | 381 | Naka, Keiji (1535) | Lost 0-2 | -171465 |
| 3standard | 708 | Krieger, Philipp (1631) | Lost 1-2 | -151450 |
| 4standard | 994 | Maruyama, Kentarou (1728) | Lost 1-2 | -131437 |
| 5standard | 984 | Tanaka, Naohiro (1384) | Lost 0-2 | -191418 |
| 6standard | 947 | Sjostrom, Jonnie (1446) | Won 2-0 | +191437 |
| 7standard | 750 | Okada, Koji (1471) | Lost 1-2 | -181419 |
| top | average opponent: 1528record: 2-5 | new rating: 1419 | ||
| Grand Prix Kobe 2014 (modern) | starting rating: 1480 | |||
| round | table | opponent (rating) | result | Δrating |
| 1modern | 745 | Yoshinari, Toshihiro (1500) | Lost 0-2 | -171463 |
| 2modern | 1074 | Nakashima, Toshihiko (1552) | Lost 0-2 | -171446 |
| 3modern | 1199 | Hirano, Nanao (1471) | Lost 0-2 | -171429 |
| 4modern | 1222 | Noguchi, Keita (1536) | Won 2-1 | +201449 |
| 5modern | 1173 | Moriyama, Masahiro (1309) | Won 2-1 | +151464 |
| 6modern | 1081 | Yamakawa, Yoshiyuki (1481) | Lost 1-2 | -171447 |
| 7modern | 1034 | Shigemune, Akinori (1448) | Won 2-0 | +181465 |
| 8modern | 964 | Awane, Hiroyuki (1480) | Won 2-0 | +181483 |
| 9modern | 881 | Kato, Yusuke (1417) | Lost 1-2 | -191464 |
| top | average opponent: 1466record: 4-5 | new rating: 1464 | ||
| Grand Prix Shizuoka 2013 (THS standard) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 625 | Takeda, Teruhisa (1500) | Lost 1-2 | -181482 |
| 2standard | 752 | Abe, Kazuki (1482) | Lost 1-2 | -181464 |
| 3standard | 887 | Goh, Yasuji (1465) | Won 2-0 | +181482 |
| 4standard | 796 | Sato, Hiroyuki (1479) | Lost 0-2 | -181464 |
| 5standard | 852 | Komatsu, Ryo (1464) | Won 2-0 | +181482 |
| 6standard | 788 | Kaido, Yoshiaki (1393) | Won 2-0 | +171499 |
| 7standard | 754 | Okada, Taro (1523) | Lost 0-2 | -181481 |
| 8standard | 710 | Kashima, Akihiro (1482) | Won 2-1 | +181499 |
| 9standard | 791 | Colobong, John (1466) | Lost 1-2 | -191480 |
| top | average opponent: 1473record: 4-5 | new rating: 1480 | ||
| Grand Prix Nagoya 2012 (RTR standard) | starting rating: 1504 | |||
| round | table | opponent (rating) | result | Δrating |
| 2standard | 375 | Yamaguchi, Yuuichi (1506) | Lost 1-2 | -181486 |
| 3standard | 612 | Yoshihara, Tomoki (1465) | Lost 1-2 | -191467 |
| 4standard | 719 | Kajita, Kazuaki (1465) | Won 2-0 | +181485 |
| 5standard | 443 | Baba, Noriyuki (1498) | Won 2-0 | +181503 |
| 6standard | 338 | Tateno, Tomoaki (1372) | Won 2-1 | +161519 |
| 7standard | 289 | Aranami, Yuuki (1489) | Won 2-0 | +181537 |
| 8standard | 152 | Suzuki, Masahiro (1485) | Lost 1-2 | -191518 |
| 9standard | 185 | Ishii, Hiroyuki (1555) | Lost 0-2 | -181500 |
| top | average opponent: 1479record: 4-4 | new rating: 1500 | ||
| Grand Prix Yokohama 2012 (modern) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1modern | 3 | Sasaki, Yuuki (1620) | Won 2-0 | +201520 |
| 2modern | 182 | Haga, Ryuji (1518) | Won 2-1 | +181538 |
| 3modern | 60 | Inoue, Hiroyuki (1515) | Lost 1-2 | -181520 |
| 4modern | 342 | Satou, Noboru (1677) | Lost 1-2 | -151505 |
| 5modern | 519 | Goto, Tomonori (1500) | Won 2-0 | +171522 |
| 6modern | 356 | Yagi, Hiroyuki (1534) | Won 2-0 | +191541 |
| 7modern | 214 | Choi, Kiho (1424) | Won 2-1 | +161557 |
| 8modern | 137 | Mochizuki, Yuusuke (1589) | Won 2-1 | +181575 |
| 9modern | 112 | Nakahashi, Yoshihiro (1577) | Won 2-0 | +181593 |
| 10modern | 62 | Miyanishi, Makoto (1522) | Lost 0-2 | -191574 |
| 11modern | 80 | Fukuda, Yousuke (1498) | Won 2-1 | +171591 |
| 12modern | 40 | Fujimoto, Yuki (1567) | Lost 1-2 | -191572 |
| 13modern | 62 | Murae, Ryuji (1591) | Lost 0-2 | -181554 |
| 14modern | 73 | Hata, Hideaki (1557) | Lost 1-2 | -181536 |
| 15modern | 72 | Yabuta, Junichi (1651) | Lost 0-2 | -151521 |
| 16modern | 64 | Yonezawa, Musashi (1579) | Lost 1-2 | -171504 |
| top | average opponent: 1557record: 8-8 | new rating: 1504 | ||