Keishiki tenpai
Keishiki tenpai 「形式聴牌」, or shaped tenpai, is otherwise known as a tenpai hand with no yaku. Some cases of tenpai also involve waiting for a so-called fifth tile, which is nonexistent. Strategically, players often push for tenpai hands regardless of yaku state for ryuukyoku to gain small points rather than lose them.