Urawa Reds defeated Ehime FC 5-1 on Sunday to clinch the last Nadeshiko League first-division championship before Japan's new professional women's soccer competition launches next year.
Veteran forward Kozue Ando was among the goal scorers for Reds, who took an unbeatable lead in the title race over second-place INAC Kobe Leonessa by securing three points in front of their home fans at Urawa Komaba Stadium.
"The support we receive (from our fans) is something we can show proudly to the rest of the world. It means a lot for us to decide the title here at Komaba," said the 38-year-old Ando, a member of Japan's 2011 Women's World Cup-winning squad.
With two rounds left in the season, Kobe are eight points adrift of Urawa and three points ahead of third-place Nippon TV Beleza, winners of the previous five Nadeshiko League titles.
The three clubs are among the 11 founding members of the WE League, Japan's first professional women's soccer league, which kicks off its inaugural season next September.
The Nadeshiko League, founded in 1989, will effectively become the second tier of women's soccer, but there will be no relegation from the WE League for the foreseeable future.