The hand
Seven pairs replaces the four-sets-and-a-pair structure with seven pairs of different tiles. In most rules two identical pairs (four of a kind) do not count as two pairs.
When to go for it
Hands with five or six pairs early are good candidates. The wait is always a single tile, so choosing a pair likely to be drawn — such as an honour already seen once — matters.
Variations
Some styles allow seven pairs only with a bonus, others not at all; American cards include singles-and-pairs hands that resemble it but follow card patterns.
Combining
In riichi, seven pairs combines well with riichi, tanyao, half flush and dora, creating surprisingly valuable hands.
