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.

Sanankou in detail

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: Sanankou allows ron as long as the three concealed triplets were completed before the ron; suuankou only forces tsumo when winning on a shanpon wait

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 two triplets, sanankou becomes impossible; only two concealed triplets can remain in the hand.

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 on a shanpon wait requires winning by tsumo (a tanki-wait ron still counts), 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 completed by the ron tile counts as open, for sanankou as well as suuankou. You score sanankou only if three other triplets were already concealed and complete before the ron.

Example: Sanankou in a real hand

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.