Fully Concealed Hands

What is Fully Concealed Hands in Japanese Mahjong?

Fully Concealed Hands is one of the fundamental one-han yaku in Japanese Riichi Mahjong. It requires you to keep your entire hand concealed and win by drawing your own final tile. Although it only grants one han on its own, it combines powerfully with other yaku like Riichi, boosting both your scoring potential and the psychological pressure you place on your opponents.

How to Achieve Fully Concealed Hands？

Fully Concealed Hand: You must not have opened your hand with any calls (chow, pung, or open kong). However, a concealed kong (ankong) does not invalidate the hand’s “closed” status, because the hand remains effectively concealed to other players.

Self-Draw: You must complete (win) your hand by drawing the final winning tile yourself, rather than claiming someone else’s discard.

Yaku Value: Achoweving Fully Concealed Hands grants one han. This yaku can be stacked with others (e.g., Riichi, Pinfu, All Simples) as long as their respective conditions are met.

No Calls Allowed: Because your hand must remain concealed, you cannot call chow, pung, or make an open kong (minkong). Doing so would forfeit the chance to claim Fully Concealed Hands.

Drawing Tiles: Since winning must come from your own draw, you simply continue to draw tiles on your turn until you complete your hand.

Combination with Riichi: Fully Concealed Hands often pairs with Riichi, because a concealed hand in tenpai (one tile away from winning) can be declared as Riichi. This can boost the total han (e.g., Fully Concealed Hands + Riichi = 2 han).

Other Stacking Possibilities: If the shape of your hand qualifies for other yaku—like Pinfu or All Simples—those can stack on top of Fully Concealed Hands. Additionally, if Riichi is declared, you can become eligible for Ippatsu or Ura Dora bonuses, further increasing your final score.

What is the Strategy and Risk of Fully Concealed Hands?

Risk vs. Reward: Committing to a fully concealed strategy can sometimes be slower, as you pass up opportunities to meld (chow/pung) that could more quickly complete your hand. However, the potential to gain multiple yaku (e.g., Riichi, Fully Concealed Hands, Ippatsu, Ura Dora) can result in significantly higher scores.

Pressure on Opponents: Opponents are often wary of a concealed hand. Once Riichi is declared, they know you are one tile away from winning, and they may adjust their discards more cautiously to avoid dealing into your potential win.

Basic Building Block: Fully Concealed Hands is considered a “basic” yaku. Learning when to maintain a concealed hand—and when to call aggressively—is a core skill in Japanese Riichi Mahjong.

Closed kong Utility: Even if you form a kong, keep it concealed (ankong) to retain Fully Concealed Hands status. This provides extra dora (the bonus tile indicator flips for each kong) without sacrificing your chance for Fully Concealed Hands.