Has an NPB (Japan) game ever ended 15-3?
Yes. NPB (Japan) has seen a final score of 15-3 31 times. It first happened on May 25, 1950, when Chunichi Dragons beat Nishi Nippon Pirates, and most recently on April 19, 2026, when Saitama Seibu Lions beat Hokkaido Nippon-Ham Fighters.
That makes 15-3 the 102nd most common final score out of 223 that have ever occurred in NPB (Japan). One point away, 16-3 has happened 20 times and 15-4 has happened 33 times.