Groenhof, Jan Pieter
Current rating: 1552
Record: 6-8-1 (GP) / 16-14 (professional)
| Grand Prix Gothenburg 2003 (MRD limited) | starting rating: 1549 | |||
| round | table | opponent (rating) | result | Δrating |
| 2sealed | 16 | Petterson, Markus (1518) | Won 2-1 | +181567 |
| 3sealed | 3 | Bakke, Geir (1611) | Lost 0-1 | -181549 |
| 4sealed | 99 | Mack, Alex (1863) | Won 2-0 | +241573 |
| 5sealed | 41 | Grondahl, Erik (1535) | Lost 0-2 | -191554 |
| 6sealed | 98 | Bemmel, Simon (1480) | Won 2-1 | +171571 |
| 7sealed | 88 | Hjelmstrom, Mattias (1538) | Lost 1-2 | -191552 |
| top | average opponent: 1591record: 3-3 | new rating: 1552 | ||
| Grand Prix Oslo 2001 (Invasion block) | starting rating: 1593 | |||
| round | table | opponent (rating) | result | Δrating |
| 1block | 116 | Rodby, Rasmus (1464) | Lost 1-2 | -211572 |
| 2block | 104 | Lia, Fredrik (1481) | Lost 0-2 | -191553 |
| 3block | 120 | Larsen, John (1464) | Won 2-0 | +161569 |
| 4block | 104 | Josefsen, Simen (1463) | Lost 1-2 | -201549 |
| top | average opponent: 1468record: 1-3 | new rating: 1549 | ||
| 2001 World Championship (mixed) | starting rating: 1482 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 53 | De Rosa, Antonino (1785) | Won 2-0 | +231505 |
| 2standard | 61 | Opalka, Jason (1623) | Lost 0-2 | -161489 |
| 3standard | 51 | Nahodil, Petr (1506) | Won 2-1 | +191508 |
| 4standard | 58 | Munoz, Eduardo (1520) | Won 2-0 | +181526 |
| 5standard | 22 | Sorensen, Jan (1578) | Lost 1-2 | -171509 |
| 6standard | 36 | Mori, Masaya (1691) | Lost 0-2 | -151494 |
| 7rochester | 65 | Nobushita, Jun (1661) | Lost 1-2 | -151479 |
| 8rochester | 70 | Richards, Scott (1596) | Won 2-0 | +201499 |
| 9rochester | 70 | Opalka, Jason (1606) | Won 2-1 | +201519 |
| 10rochester | 74 | Gallitz, Donald (1791) | Won 2-0 | +231542 |
| 11rochester | 100 | Ranque, Wilfried (1771) | Won 2-1 | +221564 |
| 12rochester | 26 | Kuo, Tzu-Ching (1710) | Won 2-0 | +211585 |
| 13extended | 17 | Williams, David A (1928) | Lost 0-2 | -121573 |
| 14extended | 31 | Matsuo, Goro (1590) | Lost 1-2 | -181555 |
| 15extended | 46 | Skrbec, Ziga (1382) | Lost 0-2 | -211534 |
| 16extended | 54 | Morita, Masahiko (1656) | Won 2-0 | +201554 |
| 17extended | 48 | Schneider, Oliver (1664) | Won 2-0 | +201574 |
| 18extended | 39 | Aperghis, Dimitris (1602) | Won 2-0 | +191593 |
| top | average opponent: 1648record: 11-7 | new rating: 1593 | ||
| 2001 European Championship (mixed) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 85 | Rosso, Daniele (1535) | Won 2-1 | +181518 |
| 2standard | 21 | Eder, Wolfgang (1678) | Lost 0-2 | -151503 |
| 3standard | 90 | Durham, Michael (1575) | Lost 1-2 | -161487 |
| 4standard | 112 | van de Logt, Tom (1710) | Lost 0-2 | -141473 |
| 5standard | 103 | Possemiers, Ben (1512) | Won 2-0 | +181491 |
| 6standard | 88 | Kunzler, Matthias (1404) | Won 2-1 | +171508 |
| 7standard | 67 | Seeberger, Jacques (1500) | Won 2-0 | +181526 |
| 8rochester | 5 | Vegna, Alessandro (1515) | Won 2-1 | +171543 |
| 9rochester | 92 | Joebstl, Markus (1923) | Lost 1-2 | -111532 |
| 10rochester | 13 | Lippert, Christoph (1748) | Lost 1-2 | -141518 |
| 11rochester | 31 | Akritas, Pavlos (1473) | Lost 1-2 | -191499 |
| 12rochester | 120 | Renko, Andrej (1533) | Lost 0-2 | -171482 |
| top | average opponent: 1592record: 5-7 | new rating: 1482 | ||
| Grand Prix Oslo 1999 (ULG sealed) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 2sealed | 33 | Ellingsen, Kenneth (1518) | Won 2-1 | +181518 |
| 3sealed | 26 | Fossaa, Kristian (1430) | Draw 1-1 | -11517 |
| 4sealed | 46 | Nitter, Hermod (1536) | Won 2-1 | +181535 |
| 5sealed | 21 | Klingenberg, Kenneth (1554) | Lost 1-2 | -181517 |
| 6sealed | 47 | Hoglund, Kim (1537) | Lost 0-2 | -171500 |
| top | average opponent: 1515record: 2-2-1 | new rating: 1500 | ||