Japanese candles are made of plant-based wax that generates less soot than other types of candles. Wicks are made by carefully wrapping dried rushes one by one around a core of Japanese paper. This process creates a cavity that extends to the top of the wick; lighting the wick incorporates air into the cavity, which in turn sucks the flame inward and causes it to sway back and forth. The unique phenomenon of a flame that flickers even without the presence of wind also means that the candle will not easily go out.