Settled region - Revision history

Selinger: /* Usage */ Added efficiency as a reason why a player might sometimes move in a settled region.

2022-12-03T15:36:22Z

‎Usage: Added efficiency as a reason why a player might sometimes move in a settled region.

Selinger: small edit and typo

2022-08-29T22:25:29Z

small edit and typo

Selinger: New page.

2022-08-28T23:13:28Z

New page.

New page

A region of the board is ''settled'' if neither player can gain anything by playing there.

== Examples ==

The simplest example of a settled region is an area of the board that is completely filled with stones. The following region is settled:

<hexboard size="5x5"
edges="top left"
coords="top left"
visible="area(a1,a5,b5,d3,e3,e1)"
contents="B all R b5--b1 a5--a1 e3"
/>

However, a region does not need to be completely filled with stones to be settled. The following region is also settled, and is in fact equivalent to the above one:

<hexboard size="5x5"
edges="top left"
coords="top left"
visible="area(a1,a5,b5,d3,e3,e1)"
contents="R b5 B c4 R e3 B e2 R a4 b2 B c3"
/>
To see why, note that, from Red's point of view, b5 is [[virtual connection|connected]] to the top edge and e3 is not. Nothing Red could do in the region could achieve a better outcome. Similarly, from Blue's point of view, e2 and c4 are connected to each other, and neither of these stones is connected to the left edge. Again, nothing Blue could do in the region could improve this outcome for Blue. Finally, the empty cells at the region's boundary, e1, d3, and a5, are such that their color does not matter, since each of them is already next to a red stone (or edge) and a blue stone (or edge). Consequently, no player can achieve anything that that player does not already have, and the region is settled.

== Usage ==

Being able to recognize when a region is settled is a useful skill, because it allows the player to focus their attention elsewhere. A move in a settled region is always a [[irrelevant move|wasted move]], and therefore neither player needs to consider moving there. (If the whole board is settled and both players know it, the losing player may as well [[resigning|resign]].)

A move in a settled region can sometimes be used as a [[time-tesuji]].

@@ Line 24: / Line 24: @@
 == Usage ==
-Being able to recognize when a region is settled is a useful skill, because it allows the player to focus their attention elsewhere. A move in a settled region is always a [[irrelevant move|wasted move]], and therefore neither player needs to consider moving there. (If the whole board is settled and both players know it, the losing player may as well [[resigning|resign]].)
+Being able to recognize when a region is settled is a useful skill, because it allows the player to focus their attention elsewhere. A move in a settled region is always a [[irrelevant move|wasted move]], and therefore neither player needs to consider moving there, except perhaps as a [[time tesuji]] or in the interest of [[efficiency]] if the whole board is settled. (But if the whole board is settled and both players know it, the losing player may as well [[resigning|resign]].)
-−
-A move in a settled region can sometimes be used as a [[time tesuji]].

@@ Line 20: / Line 20: @@
    contents="R b5 B c4 R e3 B e2 R a4 b2 B c3"
    />
-To see why, note that, from Red's point of view, b5 is [[virtual connection|connected]] to the top edge and e3 is not. Nothing Red could do in the region could achieve a better outcome. Similarly, from Blue's point of view, e2 and c4 are connected to each other, and neither of these stones is connected to the left edge. Again, nothing Blue could do in the region could improve this outcome for Blue. Finally, the empty cells at the region's boundary, e1, d3, and a5, are such that their color does not matter, since each of them is already next to a red stone (or edge) and a blue stone (or edge). Consequently, no player can achieve anything that that player does not already have, and the region is settled.
+To see why, note that, from Red's point of view, b5 is [[virtual connection|connected]] to the top edge and e3 is not. Nothing Red could do in the region could achieve a better outcome. Similarly, from Blue's point of view, e2 and c4 are connected to each other, and neither of these stones is connected to the left edge. Again, nothing Blue could do in the region could improve this outcome for Blue. Finally, the empty cells at the region's boundary, e1, d3, and a5, are such that their color does not matter, since each of them borders the region's boundary wedged between a red stone (or edge) and a blue stone (or edge). Consequently, no player can achieve anything that that player does not already have, and the region is settled.
 == Usage ==
@@ Line 26: / Line 26: @@
 Being able to recognize when a region is settled is a useful skill, because it allows the player to focus their attention elsewhere. A move in a settled region is always a [[irrelevant move|wasted move]], and therefore neither player needs to consider moving there. (If the whole board is settled and both players know it, the losing player may as well [[resigning|resign]].)
-A move in a settled region can sometimes be used as a [[time-tesuji]].
+A move in a settled region can sometimes be used as a [[time tesuji]].