Can I call a discard for a pair or single tile?
You can call a discard to complete a group of 3 or more identical tiles, not for pairs or single tiles, UNLESS this is the last tile you need for Mah Jongg
You can call a discard to complete a group of 3 or more identical tiles, not for pairs or single tiles, UNLESS this is the last tile you need for Mah Jongg