2020 Top League
The 2020 Top League was the 17th season of Japan's top tier domestic rugby union competition. The season was initially suspended after round six and later cancelled due to the COVID-19 pandemic in Japan.
Teams
| Club | Region | Previous season |
| Canon Eagles | Machida, Tokyo | 12th |
| Hino Red Dolphins | Hino, Tokyo | 14th |
| Honda Heat | Suzuka, Mie | 9th |
| Kobelco Steelers | Kobe | 1st |
| Kubota Spears | Abiko, Chiba | 7th |
| Mitsubishi Sagamihara Dynaboars | Sagamihara | Promoted from 2018 Top Challenge League |
| Munakata Sanix Blues | Munakata, Fukuoka | 13th |
| NEC Green Rockets | Abiko, Chiba | 10th |
| NTT Communications Shining Arcs | Chiba Prefecture | 5th |
| NTT DoCoMo Red Hurricanes | Osaka | Promoted from 2018 Top Challenge League |
| Panasonic Wild Knights | Ōta, Gunma | 6th |
| Ricoh Black Rams | Setagaya | 8th |
| Suntory Sungoliath | Fuchū, Tokyo | 2nd |
| Toshiba Brave Lupus | Fuchū, Tokyo | 11th |
| Toyota Verblitz | Toyota City | 4th |
| Yamaha Jubilo | Iwata, Shizuoka | 3rd |