Page "Go handicaps" Paragraph 3

For example, a 3 kyu player gives a 7 kyu player four handicap stones to allow for an interesting game with roughly equal challenge for both players.

If traditional fixed placement of the handicap stones is used, nine stones is normally the maximum handicap.

Larger handicaps are certainly possible ; but with such a great difference in strength, Black may be simply bewildered, and not understand how many of White's moves relate to his own.