Discussion was if PS4 will be YOY down, flat or up.

What do you mean by not typical Nintendo games?  Can you provide me other games beside Nintendo games because all I see is Nintendo games that are having a huge legs in Japan.
Obviously BotW isn't normal. That game is phenomenal. A great upgrade from the previous Zelda games obviously it will sell a lot. It's great game after all.  If the game is great it will sell. 
In all honesty from what I see here is Switch put a nail in the coffin for Vita. 

Also, Why 2015 is an indicator that Switch stole sales from PS4? When PS4 is inline or beating PS3 in sales? It's selling how dedicated home console are now selling in Japan. Also historically speaking Nintendo is massive in Holiday period in Japan.

At the moment PS4 is just selling like PS4. Switch is doing superbly incredible. At the moment PS4 is home for 3rd party games. That's why I keep telling it will be 2018 because that is where 3rd party Switch games will be release along side the PS4 version. 201 will be the rise of 3rd party support in Japan.

Not at all. I quote Tbone here and why I responded:

" What would be the minimum in switch taking the ps4 sales though?"

I see, but in any case Switch is selling much better than PS4 and Switch was sold out evre single week from launch, so there is no need to compare hole Switch year vs hole PS4 year.

You cannot steal sales when there's none to steal. When Switch main selling point currently is 1st party games and the other is 3rd party games at the moment and when we all know handheld is a thing in Japan.
Besides even when Switch isn't out yet PS4 is selling good and not Switch level. It didn't light the chart consistently. There are spike here and there but PS4 cannot maintain the sales after a few weeks it will drop again to 15k-25k level and also last year was FFXV, Yakuza 6, slim,  and pro launch we will need to consider that variable as well.
Bottom line is even without the Switch. PS4 never sold amazing even with games like DQ, FF, MGS, RE, Persona and etc. 

Also, when in top 20 in MC is dominated by 1st party games. Your main argument at bold  is invalid already. Currently the main selling point of Switch is the strong 1st party line up. Majority of user of Switch fans of Mario, Splatoon and Zelda or Nintendo gamers in general. We don't have any concrete data yet for 3rd party games because there are only few has managed to sell good and almost are port from older games so if not the strong 1st party line up then what's the main selling point of Switch at the moment then?

"Anyone thinking that the Switch and the PS4 are not stealing sales from one another is just being delusional. There are people out there in the world, or in this case Japan, that are choosing between the two. If both didn't exist, they would get the one that did. But since they both exist, some people are choosing one or the other". Point is simple, PS4 sales in some way would probably be better in Japan also like in rest world where PS4 is notcible YOY up, if Switch isnt so much popular in Japan.

How exactly thats make my argument invalid, fact that 1st party games are best selling Switch games doesn't mean that they are selling only to Nintendo fans. Offocurse that great and incredibly popular games like Zelda BotW, MK8D, Splatoon 2 and Mario Odyssey can be bouth and buy people that are not Nintendo fans. Like I wrote, you can buy Switch for Zelda BotW, MK8D, Splatoon 2 and Mario Odyssey even if you are not Nintendo fan because of great reception (I mean Zelda BotW and Mario Odyssey are one best critically acclaimed games ever, MK8D is one of best MK game ever and Splatoon is strongest new IP in Japan) and popularity of those games, huge Switch popularity and hype in Japan, or portability of Switch, and Switch is also home console in same time like PS4, can easily affect someone to choose Switch instead of PS4. We already seeing plenty of people that saying that Switch is their first Nintendo console in long time (in couple of generations) or even first Nintendo console ever.

Everybody clearly doesn't want it when switch has been out for most of this year and ps4 so far is having it's best year ever. 

Who said I was being serious..

And yet you refuse to discuss the key factors on why ps4 q4 2016 was so unusually high. Ps4 pro , slim , price cut + FFXV. 

No I dont refuse, but you have some problem with reading so I dont see point to reply that to you any more, for last time:

"Ps4 slim price cut, pro and FFXV" were thing world wide, not just specifically in Japan, and for every market outside Japan PS4 will have solid YOY up difference, and there is a possibilities that only PS4 in Japan will be YOY down. And again, I was very clear, last few weeks sales are basically same around 25k, even we getting closer to holiday season, that doesn't have anything with last year sales".

That point would actually hold zone wait except for the fact that the west received many more titles suited to them this Q4 then Japan. Also unlike Japan the west had some crazy price promotions. $199 BF ps4 for example. 

Again it would be weird if the west wasn't up YOY in Q4 and Japan wasn't down. 

you know... I found it really amusing to see that there´s still people out there buying 1,2,Switch....