There may be multiple charts (levels) for one song. Each chart is labeled with a difficulty level such as Single-4, Double-8, or Maniac-12.

Single indicates a chart intended to be played with one hand, and Double indicates a chart intended to be played with two or more fingers or both hands. (You don't have to play exactly as labeled.)

The number after the difficulty level (1-20) indicates the difficulty of the chart (the number of Nikochans falling). (Please use it as a rough guide.)