| Countries: |  Japan |
| Champions: | Toshiba Brave Lupus |
| Runnersup: | Yamaha Jubilo |
| Top Try Scorer: | Ruatangi Vatuvei (18 tries) |
| Prevseason: | 2003–04 |
| Nextseason: | 2005–06 |
The 2004–05 Top League was the second season of Japan's domestic rugby union competition, the Top League. Toshiba Brave Lupus won both the league round-robin and the Microsoft Cup knockout competitions.
| Team | Region |
|---|---|
| IBM Big Blue | Chiba, Kanto |
| Kintetsu Liners | Osaka, Kansai |
| Kobelco Steelers | Hyogo, Kansai |
| Kubota Spears | Chiba, Kanto |
| NEC Green Rockets | Chiba, Kanto |
| Ricoh Black Rams | Tokyo, Kanto |
| Sanyo Wild Knights | Gunma, Kanto |
| Suntory Sungoliath | Tokyo, Kanto |
| Toshiba Brave Lupus | Tokyo, Kanto |
| Toyota Verblitz | Aichi, Tokai |
| World Fighting Bull | Kobe, Kansai |
| Yamaha Jubilo | Shizuoka, Tokai |
| Top League Table | ||||||||||||||||||||||
| Club | Played | Won | Drawn | Lost | Points For | Points Against | Points Difference | Try Bonus | Losing Bonus | Points< | -- Team | P | W | D | L | PF | PA | PD | TB | LB | Pts--> | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Toshiba Brave Lupus | 11 | 10 | 0 | 1 | 463 | 166 | 297 | 9 | 1 | 50 | |||||||||||
| 2 | Yamaha Jubilo | 11 | 9 | 0 | 2 | 380 | 218 | 162 | 8 | 1 | 45 | |||||||||||
| 3 | NEC Green Rockets | 11 | 9 | 0 | 2 | 407 | 253 | 154 | 7 | 1 | 44 | |||||||||||
| 4 | Toyota Verblitz | 11 | 8 | 0 | 3 | 427 | 224 | 203 | 9 | 2 | 43 | |||||||||||
| 5 | Kobelco Steelers | 11 | 6 | 0 | 5 | 326 | 356 | -30 | 8 | 2 | 34 | |||||||||||
| 6 | Kubota Spears | 11 | 5 | 0 | 6 | 277 | 334 | -57 | 6 | 1 | 27 | |||||||||||
| 7 | Sanyo Wild Knights | 11 | 4 | 0 | 7 | 346 | 296 | 50 | 4 | 4 | 24 | |||||||||||
| 8 | Suntory Sungoliath | 11 | 4 | 0 | 7 | 307 | 282 | 25 | 4 | 4 | 24 | |||||||||||
| 9 | World Fighting Bull | 11 | 4 | 0 | 7 | 230 | 366 | -136 | 3 | 1 | 20 | |||||||||||
| 10 | Ricoh Black Rams | 11 | 4 | 0 | 7 | 207 | 370 | -163 | 1 | 1 | 18 | |||||||||||
| 11 | Kintetsu Liners | 11 | 2 | 0 | 9 | 261 | 514 | -253 | 4 | 1 | 13 | |||||||||||
| 12 | IBM Big Blue | 11 | 1 | 0 | 10 | 243 | 495 | -252 | 4 | 2 | 10 | |||||||||||
| The top 8 teams qualified to the Microsoft Cup play-offs. The top 4 teams also qualified to for entry into the All-Japan Rugby Football Championship. Teams 9 and 10 went through to the promotion and relegation play-offs against regional challengers. Teams 11 and 12 were automatically relegated. | ||||||||||||||||||||||
| [1] Four points for a win, two for a draw, one bonus point for four tries or more (BP1) and one bonus point for losing by seven or less (BP2). | ||||||||||||||||||||||
The top eight teams in the league played off for the Microsoft Cup (2005) knock out tournament, which was won by Toshiba Brave Lupus.
--------------------
------------The number of tries and goals being equal, the result was decided in favour of Yamaha by a lottery held at Hanazono after the game.
--------In the season Toshiba Brave Lupus were top of the Top League, and Yamaha were second.
See main article: 2005 Top League Challenge Series.
Fukuoka Sanix Bombs and Secom Rugguts won promotion to the 2005–06 Top League via the 2005 Top League Challenge Series, while Honda Heat and Toyota Industries Shuttles progressed to the promotion play-offs.
Two promotion/relegation matches (Irekaesen) were played with the winners qualifying for the 2005–06 Top League. The 10th-placed team from the Top League against the 3rd-placed team from Challenge 1. The 9th-placed team from the Top League against the 1st-placed team from Challenge 2.------------So Ricoh and World stayed in the Top League for the 2005–06 season.