The one-han yaku
The commonest yaku are worth one han. Riichi: declaring a ready closed hand. Menzen tsumo: winning by self-draw with a closed hand. Tanyao (all simples): using only tiles 2 to 8, no terminals or honours. Pinfu: a closed hand of four sequences, a non-value pair and a two-sided wait. Yakuhai: a triplet of dragons, your seat wind or the round wind. Iipeikou: two identical sequences in a closed hand.
Two- and three-han yaku
Seven pairs (chiitoitsu), all triplets (toitoi), three concealed triplets (sanankou), the same sequence in all three suits (sanshoku), a straight 1–9 in one suit (ittsu), and mixed outside hands are worth two han. Half flush (honitsu), one suit plus honours, is worth three han closed. Several of these are worth one han less if the hand is open.
Big yaku
Full flush (chinitsu), a single suit with no honours, is worth six han closed. At the top are the yakuman — limit hands such as thirteen orphans and big three dragons — worth the maximum.
Dora are not yaku
Dora, ura-dora and red fives add han but do not count as yaku. A hand full of dora with no yaku still cannot win. Beginners regularly fall into this trap with open hands; always check you have a yaku before calling.
