Keishiki tenpai
Keishiki tenpai 「形式聴牌」, also known as keitan or shaped tenpai, is a tenpai hand with no yaku. Such a hand cannot win, but can still win points for ryuukyoku's tenpai settlements (in most rulesets).
Strategy
Players do not necessarily aim for keishiki tenpai until late into the hand. Usually, consideration for such action begins on the third row of discards.
Even if the point gain/loss for being noten is relatively small, it can still matter when it comes to placement. When players are close in points, especially near the end of the game, the +1500 points or so can make a difference in placement. Also, there's a small chance that haitei or houtei will let you win the hand. Therefore, if pushing for keitan is safe, it can be reasonable.
However, players must be wary of other players already in tenpai, so defense considerations are important. It is better to lose points via noten than to deal into a big hand.
Rule variation
Some house rules factor keishiki tenpai into ryuukyoku, where hands even in tenpai may not receive tenpai payment. Instead, the points for noten are deducted just because the hand lacks a yaku. However, this practice is generally uncommon.
External links
- Keishiki tenpai in Japanese Wikipedia