noun, noun or participle which takes 'suru'
sorting one's tiles
Mahjong term for arranging the tiles in one's hand into a logical order, typically by suit and number, to facilitate strategic play.
from Chinese lǐ pái
配牌が終わったら、まず理牌をする。
After the tiles are dealt, first sort your hand.
理牌
Once you've sorted your tiles, start choosing which tile to discard.