| 2017 Top Challenge League | |
|---|---|
| Countries | Japan |
| Date | 9 September – 23 December 2017 |
| Champions | Honda Heat |
| Runners-up | Hino Red Dolphins |
| Promoted | Honda Heat, Hino Red Dolphins |
| Relegated | Chubu Electric Power |
| Matches played | 40 |
The 2017 Top Challenge League was the inaugural season of Japan's second-tier domestic rugby union competition, the Top Challenge League.[1]
It was played from 9 September to 23 December 2017, with eight participating teams. Honda Heat won the competition for the second time – having previously won in 2014–15 – and won promotion to the 2018–19 Top League. Hino Red Dolphins, Mitsubishi Sagamihara DynaBoars and Kyuden Voltex finished second, third and fourth respectively to qualify for the promotion play-offs, while Kamaishi Seawaves finished seventh to qualify for the relegation play-offs. Chubu Electric Power finished eighth to be relegated to the third tier regional leagues for 2018.