Sakuna's Switch edition only got a minor shipment on Amazon.co.jp yesterday and due to the timing of the shortages, it's unlikely Marvelous will be able to supply that many physical copies until mid-December. Still it will be interesting how big the first major restock will be, especially knowing how much consoles will be sold in the coming weeks in Japan.
The game remains in 2nd place on the Japanese eShop two weeks after it's launch only behind Momotaro which is the biggest 3rd Party launch on the Switch. Considering the 500K announcement it won't have much issue surpassing 1 million this year and once the stock situation is normalized I believe it will re-enter the Famitsu Top 30 and will stay there for a considerable amount of time. It's really benefiting from very strong WoM, a team that seems committed to continuing to update it and a genre that ensures strong legs.
The developers have already released a few minor updates and after the initial success, I can see Marvelous potentially investing more money into the game for a more substantial update in the coming months/quarters.
Overall it's an unexpected hit, but once again shows that Nintendo Japan's YouTube channel can sometimes provide hints about which smaller games might have the biggest potential. Next games that will test this theory are Derby Stallion, Atelier 2 & Fit Boxing 2
