Game 3 of this Pacific League first stage is a run-prevention side against a run-producing side, and the first two games were both one-run affairs decided by a single swing. What separates this decider from those games is the starting matchup. One starter has controlled this opposing lineup all season, and the other has been hittable against this opponent. Both bullpens are in different states after back-to-back days, which only matters if a starter leaves early.
Seibu wins by keeping runs off the board. It had the league's best team ERA, but it scored 88 fewer runs than Nippon-Ham over the season. In this series it has 3 runs in 19 innings: two solo home runs and one chained run. Late chances keep dying, with a double play with runners on the corners in the opener and nothing with runners in scoring position through the middle innings of the second game.
The key matchup is Hiroto Ito against that lineup. He made eight starts against Seibu this season, and every one was a quality start, with a 2.48 ERA. On the other side, Natsuki Takeuchi has a 4.15 ERA against Nippon-Ham, including a seven-run outing in September. His arm is fresh after a planned short outing at Lotte, but this lineup has knocked him out before.
Availability is already in the form. The lineups from the first two games include the season-long absences, and Reyes is back and starting for Nippon-Ham. The real workload story is in the bullpens. Fukushima, Hori and Yanagawa have pitched on consecutive days, while Seibu's late arms threw one inning each in the opener. That gap only opens if Ito is short. His record against Seibu says he usually gets deep enough that only one or two relief innings are needed.
The likely shape is a low-scoring game where Ito holds Seibu's lineup to its usual output and Nippon-Ham finds two or three runs against Takeuchi before the late innings. The market leans on home field, the tie rule that favours Seibu and Nippon-Ham's tired relievers. The better starter in this matchup and the better offence are both on the visiting side, so I'm siding with the Nippon-Ham Fighters to win the game.