Japan is the second best selling country for the ps4

[Bofferbrauer2]

The PS4 gets all the big japanese third party IPs now that the Wii U and Vita are basically dead, and Switch only starting. However, there is a distinct lack in first and second party titles designed for japanese players; with almost all IPs from Sony developed since the PS3 era are catering to western audiences. If the PS4 hadn't the widespread support of third party publishers, it wouldn't have done any better than the Wii U in Japan, just like it did in the beginning when the PS4 was just out and trailing behind the Wii U sales. With the success of the Switch, the japanese publishers may start to jump ship to Nintendos hybrid console, at which point the PS4 sales will drop hard since it would loose much of it's appeal to japanese gamers.