Definition
13579 is the section of the card built from the odd numbers one, three, five, seven and nine, arranged in patterns of pungs, kongs and pairs.
Five numbers qualify, so this section is a little roomier than 2468. Hands here often use two or three suits, so the count is by number first and suit second.
Read the full guide: How to Read the Mahjong Card: The Notation, Decoded.
See it on real tiles: the coach reads any hand and names its direction, free, at the free read. Members get the coach on call for their own games.
More terms: Pung, Kong, Quint, Pair, Charleston, Blind pass, Courtesy pass, Joker.