One of the fastest ways to get stronger at the strategy game "go" is to practice solving life and death problems. A game often depends on the life or death of a group of stones, so knowing the difference is vitally important.
Igowin Life includes over 2000 go problems, graded by difficulty. Problems are shown with random orientation and color to increase the variety to over 32,000 positions. The app tracks your progress and gives you problems that you will enjoy solving that are appropriate for your skill level, whether you just learned the rules or you are a Dan level player.
The iPhone plays against you as you solve each problem, and will challenge you with various moves.
Each go problem is an interesting puzzle which will help you on your road to mastery of this ancient game.