Has an NPB (Japan) game ever ended 12-10?
It has. 12-10 has been a NPB (Japan) final 34 times in 63,911 games. The first was Shochiku Robins beat Nishi Nippon Pirates on March 25, 1950; the latest was Chiba Lotte Marines beat Tohoku Rakuten Golden Eagles on August 21, 2025.
That makes 12-10 the 100th most common final score out of 223 that have ever occurred in NPB (Japan). One point away, 13-10 has happened 13 times and 12-11 has happened 23 times.