GoTools is the name of a computer program to analyse life and death fights in the game of go. First, a motivation for programing go is given. General aspects of the heuristic search performed in GoTools are discussed. The absolute strength and the effect of forward tree pruning are tested in a competition between GoTools and dan level human players. It is found that with a speed up of a factor of 30 the program still finds for 70% of the problems of a test set the correct first move. A suggestion is made to compare intelligence between contestants (in solving fully enclosed life/death problems) by comparing their relative increase in the time to solve problems with the increase of the difficulty of the problems. The rules of go are explained in the shortest possible form in Appendix A.