Overview
The Best ERA title is awarded to the pitcher with the lowest earned run average among those reaching the qualifying innings threshold. NPB's threshold is team games multiplied by 1.0, yielding 143 innings in a 143-game season. An ERA in the 1.00s marks ace-caliber performance, while sub-1.00 seasons are exceedingly rare in NPB history. Minoru Murayama and Shigeru Sugishita share the record with four titles each. Unlike wins, ERA is independent of run support, making it a more accurate reflection of individual pitching ability. However, since ERA is influenced by defensive quality, sabermetrics recommends supplementing it with FIP for a more complete evaluation.