This set of subsequent exercises is meant to make the pupil aware of the breathing points available to his or her stones. The better a group can breath, the harder it can fight. Keeping track of "liberties" (breath access points) therefore is an essential skill in Go.
Like in usual Go, all strings of stones need access to at least one breathing point (liberty). As soon as a string is blocked from its last liberty, the capturing game is over, with the color of that suffocated string losing. An attacking stone is allowed to pause breathing momentarily while removing the last liberty of an opponent`s string.
In this game, all strings of stones need access to at least two liberties. The first string with only one liberty left makes its color lose the atari game immediately. An attacking stone is allowed to pause breathing momentarily while removing the second last liberty of an opponent`s string.
Even harder, all strings of stones need access to at least three liberties here to stay in the game. The first string with only two liberties left makes its color lose immediately. An attacking stone is allowed to pause breathing momentarily while removing the third last liberty of an opponent`s string.
In those breathing games above, if all strings manage to keep the required count of liberties throughout the game until the players agree to end it, the result is determined according to ordinary area scoring. Alternatively, e. g. if the pupil is a child, the secondary goal can be to place as many stones on the board as possible (see also stone counting as teaching method). In that case, the player with the higher count at the end wins.
A liberty can be protected in various ways. The protection can be ultimate or limited by time or value, applying to either color or to both.
Explanation, examples (single point eyes, almost filled eyes, seki corridors, false eyes, tiger mouths), exercises.
A string needs access to at least two protected liberties to be protected on its own. The degree of that protection depends on the weakest of the two liberties it relies on. Where one of them is protected temporarily only, the string`s status is unstable, too.
Explanation, examples (combinations of single point eyes, almost filled eyes, seki corridors, false eyes, tiger mouths), exercises.
The protection of an ensemble of strings depends on the weakest member. If all member strings are protected with all the decisive liberties neighboring strings of that ensemble only, their protection is stable. Hence, the entire ensemble then is protected permanently as a whole and said to be alive.
Its protection may nevertheless be limited by value, which is why e. g. a seki can occasionally serve as a (losing) ko threat.
Explanation, examples (incl. plain two eyed life, two-headed dragon, seki with eyes, seki without eyes; counterexamples: false eye, eye vs. no eye, temporary seki), exercises.
Special case: Pass-Life
Protected life of a one-colored ensemble (group). All concerned liberties are ultimately protected.
No defense required, regardless of any attacks.
Explanation, examples (two-eyed life), exercises.
Some (pairs of) moves left until protected life.
Explanation, examples, exercises.