Sanankou

Sanankou

Sanankou (三暗刻, さんあんこう) is a 2-han yaku where you have three concealed triplets (ankou) in your hand. These triplets must be formed without calling pon—either self-drawn or present in your starting hand. Sanankou is one step below the yakuman suuankou (four concealed triplets) and demonstrates significant hand strength.

Detailed Explanation

Requirements

To achieve sanankou, you need:

• Three triplets: Three sets of three identical tiles each
• Concealed: All three triplets must be formed without calling pon
• Can win by ron or tsumo: Unlike suuankou which requires tsumo, sanankou allows ron wins

For example: 5-5-5 bamboo (drawn), 7-7-7 characters (drawn), East-East-East (drawn), plus one more meld and a pair.

Concealed vs. Open Triplets

Concealed (ankou): Formed by drawing all three tiles yourself, not calling pon. These count for sanankou.

Open (minkou): Formed by calling pon on another player’s discard. These do NOT count for sanankou.

You can have one open triplet in your hand and still score sanankou with your three concealed triplets. However, if you call pon on more than one triplet, you risk losing sanankou entirely.

Strategic Implications

Toitoi Compatibility: Sanankou pairs naturally with toitoi (all triplets). If you’re building toitoi (four triplets), keeping three concealed adds sanankou (2 han) on top of toitoi’s value (2 han), for 4 han total before dora.

Risk vs. Speed: Each pon call speeds up your hand but destroys a potential ankou. Players must balance between calling pon for speed and keeping triplets concealed for sanankou value.

Path to Suuankou: If you have three concealed triplets and are close to forming a fourth, you might aim for suuankou (yakuman). However, suuankou requires winning by tsumo, while sanankou allows either tsumo or ron.

Ron vs. Tsumo Consideration

Winning by tsumo: All triplets remain concealed. If your fourth meld is also a triplet, you might score suuankou (yakuman) instead of sanankou.

Winning by ron: The triplet containing your winning tile is NOT considered concealed for suuankou purposes (though it still counts for sanankou). This prevents suuankou but allows sanankou.

Usage Example

You draw three 6-bamboo tiles and three 8-character tiles early in the hand, forming two concealed triplets. Later, you draw two White dragons and call pon on the third—this forms an open triplet (not concealed). Finally, you draw three 4-dot tiles, creating a third concealed triplet. Your hand: 6-6-6 bamboo (ankou), 8-8-8 characters (ankou), 4-4-4 dots (ankou), White-White-White (open pon), and a pair. You score sanankou (2 han) for your three concealed triplets plus toitoi (2 han) for all triplets = 4 han minimum.

Related Terms

Suuankou: Four concealed triplets yakuman. The upgraded version of sanankou requiring all four triplets concealed and winning by tsumo.

Toitoi: All triplets yaku (2 han). Naturally compatible with sanankou since you’re building triplets.

Triplet: Three identical tiles. Sanankou requires three concealed triplets.

Ankou: Concealed triplet formed without calling pon. Sanankou specifically requires ankou, not minkou (open triplets).