Has an NPB (Japan) game ever ended 14-6?
Yes. NPB (Japan) has seen a final score of 14-6 27 times. It first happened on April 18, 1950, when Chunichi Dragons beat Osaka Tigers, and most recently on July 13, 2021, when Tokyo Yakult Swallows beat Yomiuri Giants.
That makes 14-6 the 106th most common final score out of 223 that have ever occurred in NPB (Japan). One point away, 15-6 has happened 13 times and 14-7 has happened 24 times.