Question: I’ve heard a White Dragon (Soap) is also considered a neutral tile. What does this mean?

Answer: White Dragons (Soap), when represented as a zero, are considered neutral. When used as a zero, the soap isn’t considered a Dragon and isn’t required to match their partner suit. Therefore, in a year grouping such as 2023, the 2s & 3s can be either Craks, Bams or Dots.

Source: Mah Jongg Made Easy 2020 page 6 para. 3