When it's all said and done for the PS4, how much do you think it will sell? I see a great amount of support next year for Japan and I honestly think it will sell 8 million, 10 million is definitely possible but just to be safe I'm going with 8 million.

EDIT 2/4/15: I'm going with 15 million, fuck it. It's looking good for PS4.

Not well. But how not well is hard to say. The PS3 is at 10m and it's not getting anywhere close to that, but I really don't know. 6m? 7m? Don't know.

do you have any idea why consoles have not been selling well in japan? like everywhere else consoles have grown but in japan they've just died. do you have any idea why?

Until we see how the PS4 sells with a proper Japanese library (not just major cross gen titles like MGS5, but 8th gen exclusives like FF15), it's very difficult to guess. I don't see it having a chance at 10m though. It took the PS3 7+ years to achieve that, and during a time when the Japanese market was more accepting of home consoles.

The next years are going to be very big.
I think it will reach 7-8 million, but I hope for 10 million!

I think it will outsell the PS3 lifetime. I would guess probably 12 - 13M. This year it sold almost 1M units without really bringing anything of interest to the Japanese market. Next year will see a huge influx of titles that sell well in Japan, but it will still be a little slow due to cross gen with PS3. When I see thing really taking off is 2016. By then I expect Sony to have ironed out any issues with PS Now and Remote Play. I think both will be on most any mobile device, and they will have the ability to stream over 4G. Once this happens, I see most of the big Japanese games going to PS4, as they will be playable both at home and on the go.

its getting really hard to take you seriously these days. the PS4 is already at around 1M in Japan with just 10 months over there. and not a single major Japanese centric game has been released yet. and so far on the ps4 more Jrpgs have been announced to be coming to the ps4 already than there were jrpgs released on the ps3 in 7 years. 

I feel the ps4 will at the very least do 8M in Japan, though I have it pegged to just edge out the PS3 in sales.

Really its too early to tell seeing as we havent had a real Japanese library to push sales yet.
I voted 15m but really all I mean is more than Wii. So far it looks like a lot of Japanese devs are jumping on board and I hope 2015 can be its first successful year.

Edit: Oh this is based on it getting DQXI exclusively, that one is really important.

No option for less than 5m? :P

Way too early to tell but I'll say 6-7 million.