Li is the female or Yin-half.
Numerologically Kan is the Sun and Li is Mars. But Kan remains the "1" or Sun even if you put a 9 to it. Kan doesn't change with it. This is the mystery.
PS. The full numbers of Kan are 1-7-8 and Li 9-3-3. They are in balance regarding the masculine and femininen numbers when compared to each other.