Just for some context, the PS4 sold almost one million in it's launch year. Keep in mind it launched in March in Japan, similarly to what the Switch did. And during much of that time, it was beaten on a weekly basis by the Wii U of all things.

The PS5 will do even worse. It's bigger by a significant amount as you can see below, even dwarfing the "fat" PS3, which is a massive drawback in Japan where space comes at a premium, and the Playstation brand has be seriously neglected over there in favor of the west, specifically Europe.

PS4 had a least several games in the COMG! chart before launch, and some of them did quite decently there. Compare that to only Spiderman for the PS5, and that one being at the bottom of the chart doesn't bode well for the system or any enthusiasm into it. There are currently also no PS5 games charting there either despite going as low as 3 points, so the outlook so far is not great, either.

It's certainly going to be very interesting to watch how PS5 fares in Japan, but at the outset, if I had to guess, I'd say it will continue the decline over its predecessor that every PS system has had in Japan since the PS2.

I think a lot will depend on how aggressively they pursue and moneyhat Japanese exclusives; I can see them writing an exorbitant cheque to get Dragon Quest, and Monster Hunter World's successor is almost certainly already in development for it, along with Final Fantasy 16. Then again, PS4 had mainline entries in all three and still sold less than the PS3 so even throwing their wallet around might not help enough.

Dragon Quest exclusive? don't think so. 

The common sense thing would be to make Dragon Quest 12 for Switch, but third parties often don't act rationally. Crazier things have happened.

Dragon Quest is solely under the control of it's creator Horii not SE he alone decides which is why the was a Switch version of DQXI before the platform was even revealed SE themselves would have just had DQXI as PS4 only with no 3DS version. Horii imposes a strict rule to always be on the most successful platform in Japan this is why DQ has never declined in Japan because it always hits the biggest userbase and renders it impossible for PS brand to get it exclusive unless they can outsell the Switch at this point they would be paying to just have a version of the game as Horii never deviates from this rule every game has followed this rule since the series creation.

Sakuna on the Switch facing shortages in Japan, looks like the initial shipment was sold and now the physical version is selling for about twice the price on Amazon. The initial shipment on the Switch is unlikely to be higher than 30K, the more likely case is around 20K.

#天穂のサクナヒメ #sakunaofriceandruin facing shortages on the Switch in Japan. The physical version of the game selling for nearly twice the retail price
Congrats to @marvelous_games for the successful launch - hopefully, they can ship a lot more copies to Japan for the holidays pic.twitter.com/UbxTfxRPtz

— Nocturnal (@Noshten) November 15, 2020

There is also going to be a surprising result later in the fall as Derby Stallion is looking more and more likely to end up in the Top 50 on Famitsu with enough stock. I won't be surprised if it ends up beyond 150K sales in 2020. 

One of the games that will do surprisingly well this holiday season. You could say it's a Dark Horse for the Top 50 best selling games this year in Japan

The price of the game is the equivalent of $70

Derby Stallion sold 1.7 million on the PS1 back in the day#derbystallion pic.twitter.com/enH6oVDUH1

— Nocturnal (@Noshten) November 15, 2020

Looking at COMG ranking the launch of the PS5 will actually have launches a lot lower than expected, at this point I'm wondering if Demon Souls even surpasses 20K physical at launch. 

So, another case of a dev underestimating Switch software demand and undershipping?

Some interesting tidbits about the Switch's software numbers based on Nintendo's own reports:

According to Nintendo themselves, these are the best selling Switch games in Japan (shipped+digital)

1. Animal Crossing: New Horizons - 8.18 million
2. Super Smash Bros. Ultimate - 4.82 million
3. Pokemon Sword/Shield - 4.77 million
4. Splatoon 2 - 4.35 million
5. Mario Kart 8 Deluxe - 4.04 million
6. Super Mario Odyssey - 2.53 million
7. The Legend of Zelda: Breath of the Wild - 2.21 million
8. Super Mario Party - 2.07 million
9. Ring Fit Adventure - 1.8 million
10. Super Mario Maker - 1.16+ million*
11. New Super Mario Bros. U Deluxe - 1.13 million

(They didn't list Super Mario Maker in their updated Million Sellers list for the fiscal year. But their last figure on the game is still higher than NSMBUD's current figure, so it is still higher.) Will be interesting to see if Pikmin 3 will have any chances of cracking 1 million? Will Age of Calamity be able to do it? And where will Monster Hunter Rise rank on this list?

Difficult to say where Monster Hunter Rise will rank, I think it will be the top selling Monster Hunter game in Japan - but how high can it get depends on whether Capcom cuts it's legs short by releasing Monster Hunter Rise Deluxe or something.

In unrelated news Marvelous's share price had to be temporarily halted due to an unanticipated surge—they capped it at ¥942, and it closed at ¥875 (+¥83 / +10.48%). This is mainly due to investors not expecting Sakuna to do so well(still sold out physically on the Switch across Japan), Top of the eShop, Top on Steam... This was a game made by two people, so it must be really profitable. Fantastic news for Marvelous ahead of the release of their big titles next year - Olive Town and Rune Factory 5.