Kokushi Musou, also known as “13 Orphans”. It’s a hand in Mahjong, one of the most expensive hands i.e. a “Yakuman”.
You form this hand with one Honor and one Terminal of every suit plus an extra of any type. By “honors”, I mean the Haku, Hatsu, Chun (the Dragon title), Ton, Nan, Xia, and Pei (the Wind Titles- East, South, West, North respectively.) For the Terminals, I mean a 1 and 9 of each suit: the Souzu (Bamboo), Pinzu (the circles), and Manzu (the Character titles).
This one is even more special, though: it’s a 13-sided Kokushi Musou, meaning it can win on any duplicates of the titles that’s already in your hand. Usually, you have to win on a specific title while already having a duplicate of any title in your hand. For example, if you have every title but the Haku while having two of the 1-Manzu, you have to wait on the Haku to complete that hand.
This is what years of reading Mahjong manga will get you, kiddies.