This doesn't count the digital sales, retail sales of digital codes and bundles. These are the best 10 selling games in Japan this year so far according to Famitsu.
1. [3DS] Yo-Kai Watch Busters: Red Cat Team / White Dog Squad: 1.597.600 (Released: July 2015)
2. [3DS] Animal Crossing: Happy Home Designer: 1.124.502 (Released: July 2015)
3. [3DS] Dragon Quest VIII: Journey of the Cursed King: 850.175 (Released: August 2015)
4. [WIU] Splatoon: 763.086 (R: May 2015)
5. [3DS] Yo-kai Watch 2: Shinuchi: 604.748 (R: 2014) )
6. [3DS] Fire Emblem Fates: Birthright / Conquest: 529.231 (R: June 2015)
7. [3DS] Rhythm Heaven: The Best+: 503.703 (R: June 2015)
8. [PS3] Dragon Quest Heroes: The World Tree's Woes and The Blight Below : 453.142 (R: February 2015)
9. [3DS] The Legend of Zelda: Majora's Mask 3D: 439.268 (R: February 2015)
10. [3DS] Pokémon Omega Ruby/Alpha Sapphire: 429.364 (R: 2014)
Poor all the non-Nintendo others, not Dragon Quest Heroes being the only one game published on a Sony platform that made it to the top

However, the PS4 versions of MGSV and other games still charted high according to weekly sales figures.
Slay @ Yo-Kai Busters selling (if we count digital sales) nearly 2M in less than 4 months, it will probably surpass the two million mark when the year ends
Also, the Yo-Kai Watch 2 re-release holds very strong with those sales, you have to evaluate that the content added in this third version was also available for free for everyone who bought the original versions and people still bought the re-release
With this, the Yo-Kai franchise scores 3 million sellers out of 4 games on the market: YW1 (2013) with +2M sales, YW2 (2014) with 4'5M sales and YW:Busters (2015) with 1'7M sales.
The Yo-Kai reign just won't let up!
The DQVIII port and Animal Crossing spin-offs also show very strong numbers in such a short amount of time on the market. ORAS also seem to have stronger legs than XY, which stopped selling as much with time, maybe that's because of no new mainline game being released this year and the movie actually being decent this year.
For the rest of the year, I expect Dragon Quest Builders to take ORAS spot and Yo-Kai Busters to rise its sales as there is a third version coming as a free DLC in the next weeks. I don't think the Animal Crossing Wii U game will sell enough to put it in the Top 10, though.
So, what do you think about the Top 10? Did your fave make it? Did you play or are interested on playing any of the games above when they get released over here?