Lost Judgment - Generally a very tough choice between this and the original Judgment but the sequel just about edges out for me. Incredibly story with a fantastic rival and genuine awesome clash of ideals/beliefs, the best combat system in an RGG game to date, godlike soundtrack, some of the best, most meaty side content the series has had to offer, just frankly one of the best overall games RGG has ever put out.

Yakuza 6: The Song of Life - I adore this game, it perfectly ends Kiryu's story in such a grand, climactic, emotional way I can't help it. One of the few games to make me cry at it's ending every single time, and the whole story is equally emotional and well put together. It might also outright be my favorite RGG OST (either it or Y3), it has some of the best long battles in the series, some of my favorite boss battles in the series, and was probably the prettiest game in the series until Lost Judgment rolled around. Only thing really holding it back is the combat being a bit rough.

Yakuza 0 - Best overall Yakuza game imo, incredible story, the best combat RGG had to offer until Lost Judgment rolled around, the best multi-character offerings in terms of combat and storytelling, the world is jam packed with shit to do, the progression loop is satisfying as hell, the boss battles and long battles are generally excellent, and its a perfect start to Kiryu & Majima's storylines. Just a fucking solid game that fires off on all cylinders from the moment go.