Tsumego, a Japanese go term adopted into English, are problems mainly about life and death, but also about ko, capturing races, cutting, connecting, etc. As a rule they are local problems, but a few involve the whole board.
There are many published collections of tsumego, or life-and-death problems, many in Asian languages but increasingly many in Western languages. Many collections are available on the internet. SL also has a growing collection of go problems.
Most professional players and top amateur players agree that solving tsumego is one of the best ways to improve. Tsumego solving improves your reading ability overall and sharpens your sense of danger in life and death situations.
It is important to know how to approach a life and death problem. We have a few pages discussing this topic.
- How to approach a life and death problem.
- Beginner's Guide to Tsumego
- Tsumego conventions
- A New Approach to the Creation of Go Problems
- Yu Ping on Tsumego
- The Important Skill of Calculation Starts With Doing Life and Death Problems
Some related terms
- Tsumego Speed And Accuracy Table
- Take a bet on life and death - a tsumego tournament variant
- Standard Normal Form
- Panda Sensei - tsumego solving AI
- List of Major Works of Japanese Tsumego
 Simply 死活题, because 题 = 问题 = question/problem rather than Wéiqí = Go / sǐhuó = die/live / wèntí = problems => 围棋死活 and/or 死活问题
 In his "Commented games volume 1", Lee Sedol says playing relatively fast games and reviewing them as the most effective method. Playing through professional games and learning the principles of go are also important.