I noticed the game uses 54 cards, so I tried to re-interpret it with a standard deck of 54 playing cards (including jokers) to make it playable if you have a deck lying around:
- Each player gets 6 cards, not revealed to other players.
- The rest go in the pile in the middle.
- Players take turns. Each player, in each turn:
- Discard a card of your choice to the bottom of the pile.
- Draw a card from the top.
- If you draw an ace or joker:
- Pick a player. Look at their hand, and steal a card of your choice.
- They draw a card from the top to replace the stolen card.
- Pick a player. Look at their hand, and steal a card of your choice.
- If you have at least one of each card from the groups 2-3, 4-5, 6-7, 8-9, 10-J, Q-K, they form a pichun: you have the option of pichun-ing someone. Discard those 6 cards and remove a player from the game for 10 rounds. After 10 rounds, they re-enter: both players discard their hands and redraw 6 cards.
- If you have a pichun with all the same suit, you can perform a "max pichun" and win the game outright.
- If there's only one player active (not pichun-ed) they win.
Explanation: Each suit corresponds to the four fairies (Cirno + three fairies of light). You're supposed to have 8x of each letter in "pichun", 2 of each with the same character on it, which I represented by groups of playing cards: p: 2-3, i: 4-5, c: 6-7, etc. Having a pichun with all the same suit corresponds to having a pichun with all the same character. The deck is also supposed to have 6 "steal" cards, which I interpreted as aces or jokers.
Rule clarification: I make the assumption that when you steal, you get to choose the card to steal, and can look at their hand when doing so. Otherwise, stealing isn't advantageous.
I played a round by myself with two players, and it seemed like a decent enough card game. Would probably be much better with 3-4 to make the max pichun a relevant element (with two players a regular pichun is equivalent to a max pichun).