ダマテンとリーチの使い分けが下手。
たとえば、
のような「役があり悪い待ち」「待ちを変えやすい」「リーチしても点数が倍にならない」でリーチをかけてしまう。
（以下、欧米向け。下手な英訳ですから突っ込み大歓迎ですよ～）
Mahjong; 10 of Mistakes' : 6
6. Unskilled riichi. This has many patterns.
e.g.
The player should not call riichi becuase 3 reasons. One is this hand has Yaku(mixed triple chow and
), so the player can go out by discarding tile without riichi. Two is the wait is bad shape. And the last is this riichi has unefficiency. without riichi 5200pts.
with riichi 8000pts.(not 2 times by riichi)