Sets may include flower, season or joker tiles. These are not used in riichi mahjong (1.3); Japanese sets often include red fives, each normally worth one han. Red fives are not used under EMA riichi rules (1.3)
Why people argue about this
People often assume that red fives are still valid in riichi mahjong under EMA rules simply because they're common in Japanese sets. However, the official verdict clearly states that red fives are explicitly excluded from being used in riichi mahjong under these specific EMA (East Asia Mahjong Association) guidelines, leading to misunderstandings and arguments about their validity.
