Problem Types Supported by the 101 Problem Library
Life-and-Death Problems
These problems ask whether a group of stones is alive or dead—one of the most important fundamentals in Go. Once a game begins, neither side can make every group alive immediately, so life and death remains relevant from the opening through the end of the game. Both players must recognize the right moment to attack an opposing group or secure life for their own stones.
Life-and-death problems range from very simple to extremely complex. In a simple shape, a single move may determine whether the group lives or dies; a complex position may require reading dozens of moves. At the end of a game, the status of groups also forms the basis for counting territory.
Tesuji Problems
Tesuji means the best tactical move in a local position.
In Go, the underlying idea is the relationship between stones. A particularly effective technique that makes the most of those relationships is called tesuji.
Tesuji uses stones with maximum efficiency and reveals a player's precise, resourceful thinking and strength. Mastering tesuji makes it possible to handle complex fighting. An ordinary move in a fight is not necessarily tesuji; the term is reserved for an ingenious, often unexpected move.
Capturing Problems
Simple life-and-death problems in which the opponent's stones can usually be captured in one move.
Endgame Problems
The endgame is the last of the three broad stages of a Go game—the opening, middle game, and endgame. After the main fighting has largely settled the territory and the status of groups, both players compete to define the remaining boundaries.
Endgame problems ask you to find the largest move during this stage.
Joseki Problems
Joseki are established sequences that both players generally follow in certain situations, developed through the accumulated experience of Go players over many years.
They most commonly occur in the corners during the opening, although some established sequences in the middle game are also called middle-game joseki.
Opening Problems
The opening, or fuseki, is the initial stage of a Go game.
A game is usually divided into the opening, middle game, and endgame. Because the goal is to secure territory, both players claim open areas of the board during the opening while limiting the opponent's potential, leading into middle-game fighting.
There is no exact boundary between the opening and the middle game. Some games enter the middle game only after all the large open areas have been divided; others begin with an intense fight in one corner that spreads across the board.
With relatively few stones on a large open board, precise calculation is difficult. Opening problems therefore test whole-board judgment and intuition.
Appreciation Problems
Positions that contain mistakes but come from games by famous players and are presented for appreciation.
Trick-Play Problems
A trick play is a deliberately unreasonable move that tests whether the opponent can identify its weakness. If the opponent responds incorrectly, the player using the trick gains a large advantage; if answered correctly, the trick play incurs a loss.
Middle-Game Fighting Problems
Problems that test attack and defense during the middle game.
Imitation Problems
Watch a move sequence and then reproduce it. These problems are often used to train joseki memory.
Go-Principle Problems
Problems that test your understanding of Go principles.
Opening/Middle-Game/Endgame Guess-the-Next-Move Problems
Choose a game record and guess the next move.
Stone-Placement Problems
Place stones on the board according to the problem author's instructions—for example, mark the four liberties of a stone.