2003 JMRCA 1/8 GP Off-Road Japan Championship
September 5-7, 2003
Mugen MBX-5 First Title!
TQ & Winner: Yuichi Ajishi (MBX-5)
| Pos. | Name | Car | Qly.pt (Pos.) |
| 1. | Yuichi Ajishi | Mugen | 246pt. (1) |
| 2. | Yuichi Kanai | Kyosho | 246pt. (2) |
| 3. | Kenji Osaka | Mugen | 244pt. (3) |
| 4. | Tamotsu Kuzuya | Mugen | 238pt. (6) |
| 5 | Atsushi Kawamoto | Kyosho | 241pt. (4) |
| 6 | Daisuke Endo | Mugen | 229pt. (11) |
| 7 | Makoto Mogi | Kyosho | 216pt. (21) |
| 8 | Hideki Kobayashi | Kyosho | 238pt. (5) |
| 9 | Toru Hirao | Mugen | 234pt. (8) |
| 10 | Koichi Kaneda | Mugen | 212pt. (22) |
| . |
| 2003 Japan Championship was held at Madarao Park from September 5 to 7. |
| 118 drivers joined this championship who qualified the each district qualification. |
| Top qualifier was Ajishi, 2nd. position was Kanai, and 3rd. was Osaka. |
| Top two drivers was seeded to the grand final. Other drivers have to jump up |
| from lower main final. The top position of Semi-final was Osaka and Kuzuya. |
| And, the top four drivers from Semi-final A&B jumped up to grand final. |
| It was total of 5 round of qualification (counted best 3 round), but due to the |
| weather condition (dense fog), 4th. and 5th. round was canceled. |
| So, it was total of 3 round of qualification and counted best 2 round. |
| The grand final was also canceled due to the weather condition (dense fog), |
| but semi-finals and lower finals was finished completely. |
| So, the final result was decided by grid number for grand final. |