The key determinant of playing strength is the ability to read out a problem. This comes from practice. We learn from our successes. We learn from developing the reflex of looking in the right place for successful moves.

Playing gives us this practice, but can result in bad habits, when poor moves are left unpunished.

The graded go problems are an excellent series, based on teaching problems used in Japan. Volume four continues where volume three leaves off and the problems are grouped getting less easy as you go on.

If you are a beginner, you should buy volumes one to four and work through them. If you have volume two, buy three and four today. Volume four,ostensibly for players of 15 - 10 kyu, will profit even low kyu players.