Editing Go (game) (section)

=== Seki (mutual life) ===
[[File:Goseki.png|thumb|Example of seki (mutual life). Neither Black nor White can play on the marked points without reducing their own liberties for those groups to one (self-atari).]]

<!-- DEPRECATED as too complex.
<div class="thumb tright">
<div class="thumbinner" style="width:202px; font-size: 100%;">
{{Goban 9x9
| ul|  b|  b|  w|  u|  w|  u|  u| ur
|  b|   |  b|  w|  w|  w|  w|  w|  w
|  b|  b|  w|  w|  b|  b|  b|  b|  b
|  w|  w|  w|  b|  b|   |  b|   |  b
|  b|  b|  b|  w|  b|  b|  b|  b|  b
| lc|  c|  b|  w|  w|  w|  w|  w|  b
|  w|  w|  w|  b|  w|   |  w|  b|  b
|  b|  b|  b|  b|  w|  w|  w|  b|  r
| dl|  b|  d|  b|  w|  d|  w|  b|  b|22}}

<div class="thumbcaption" style="font-size: 88%;">
Example of seki (mutual life). Neither Black nor White can play on the marked points without reducing their own liberties for those groups to one (self-atari).
</div>
</div>
</div>
– Above deprecated. -->
There is an exception to the requirement that a group must have two eyes to be alive, a situation called ''seki'' (or ''mutual life''). Where different colored groups are adjacent and share liberties, the situation may reach a position when neither player wants to move first because doing so would allow the opponent to capture; in such situations therefore both players' stones remain on the board (in seki). Neither player receives any points for those groups, but at least those groups themselves remain living, as opposed to being captured.{{efn|1=In game theoretical terms, seki positions are an example of a [[Nash equilibrium]].}}

Seki can occur in many ways. The simplest are:
# each player has a group without eyes and they share two liberties, and
# each player has a group with one eye and they share one more liberty.
In the "Example of seki (mutual life)" diagram, the two circled points are liberties shared by both a black and a white group. Both of these interior groups are at risk, and neither player wants to play on a circled point, because doing so would allow the opponent to capture their group on the next move. The outer groups in this example, both black and white, are alive. Seki can result from an attempt by one player to invade and kill a nearly settled group of the other player.{{sfn|Matthews|2002|p={{page needed|date=May 2014}}}}