The best thing about Yakuza 0 isn't just that it's a damn fine video game, it's that it serves as the perfect entry point for newcomers to a series that is thick on gangster lore. Once you're done, the credits roll and you are mad for more Yakuza, though, you're left with a question: what Yakuza game do I play next?
It's not an easy one to answer! Yakuza 0 is a 2017 (well, 2015 in Japan) prequel for a series with five other main games in it, the first one dating back to 2005 and its sequels spread across multiple platforms. So while you'd assume playing Yakuzas 1-5 in order would be the correct thing to do, you would in fact be very wrong and would be making a terrible mistake.
The five main Yakuza games that are currently available in the West (Yakuza 6, which is already out in Japan, won't be released here until 2018)
Forget the first Yakuza game (at least for now...I'll explain later). It was released on PS2, and the English language version was given a celebrity dub featuring -- and I swear this is real -- performances from actors like Mark Hamill, Michael Madsen, Rachel Leigh Cook, Eliza Dushku and...the A-Team's Dwight Schultz.
This ruins the game, as half the point/fun of Yakuza games is that they're as Japanese as Japanese video games get, from the fashion to the characters right down to the cans of CC Lemon. It's also a janky-arse PS2 game whose combat is nowhere near as fun as the later games. So give it a miss.
You can skip Yakuza 2 for similar reasons. While this one ditched the English dub, it's still a PS2 game, and going back in time like that is going to be rough on anyone who has just played a PS4 game for 50+ hours.
Yakuza 3 is the first "modern" Yakuza game, making the jump from PS2 to PS3. Because of this, and because the game's English version was an attempt by Sega to reboot the series in the West following the disastrous reception to the first game, it includes a massive collection of cutscenes designed to introduce you to the complex politics and backstory of the series, which it's recommended you watch before playing the game.
Don't bother. You can watch that stuff on YouTube (along with the game's main plot itself), and Yakuza 3, while a good game, is nowhere near as fun as 4 & 5.
Yakuza 4 is where you should start. Not only is it the best Yakuza game, by virtue of a snappy story that switches you between four different players and keeps things interesting throughout, but it also has large retro sequences detailing some of the events before Yakuza 0, so you'll be sliding right into familiar territory.
In addition to the main games, there have been three spin-off Yakuza titles. Two of them -- a PSP game and a PS3 one set in medieval Japan -- were never released in the West. The third, a zombie shooter called Dead Souls (pictured), was; play it if you want, but it's not very good.
After that, hit Yakuza 5, which is basically a straight sequel to 4 (duh), not just in terms of story but because it also has the "swap between multiple characters" thing going on. It features a new engine (the game was also released on PS4 in Japan), so you'll notice that aside from some texture quality it's very similar to Yakuza 0 in terms of visuals. Oh, and it's also an excellent game, and it will let you see how Yakuza's version of Osaka has changed in the years since 0.
Of course, this is assuming that you want to play a Yakuza game right now. If you think you'll be spending a few more months playing 0 before moving on, then I have some good news: a full HD remake of Yakuza 1, called Yakuza Kiwami, is on the way and is due out in the West in the Summer.
It's not a HD remaster, it's a complete HD remake, with new visuals, new combat, new side-missions and even an all-new recording of the game's Japanese dialogue, done by the original voice-actors.
Plus, if you're fresh of playing Yakuza 0, Yakuza Kiwami's antagonist will be awfully familiar...
Since this fixes most of the issues with the first Yakuza, then Kiwami would be the one you should start with, followed by 4, then 5. If you can wait. If you can't, play 4 then 5.
This is a stupid way of approaching a video game series, I know. Part of that is just down to the nature of the Yakuza series itself, doing silly things like dropping a prequel in as the sixth game in a series. Part of it is down to Yakuza now reaching across three different PlayStation home console generations, and part of it is because Sega fucked up Yakuza 1 so badly in the West that we very nearly didn't get Yakuza 3 -- and by extension every game since -- in English at all.
What you need to realise looking at this mess, though, is that despite my recommendations, it doesn't really matter. Start at 0, play 4, then 5, then 3 if you want, who cares. Nobody plays Yakuza for the story. It's a series about characters, about hilarious sidequests, about virtual tourism, about brutal combat.
Sure, there's always some meta conspiracy or power struggle dragging you through each game, but those primary plot points are explained well enough in isolation during each game (or in lengthy cutscenes you can watch externally) that it's not like you'll enter at 4 or 5 and feel truly lost.
Just run around, buy some drinks, punch some dudes, help some people and listen to some quality voice acting. That's what Yakuza games are really about. So take my advice if you're serious about the series' characters and lore, but if you're just in this to crush skulls with bicycles, then play what you want!