Difference between revisions of "A3 escape trick"
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(Emphasize that this is a special case of a switchback.) |
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| − | + | '''"A3 escape trick"''' is an older name for the [[Switchback#A3 switchback|a3 switchback]]. It dates from a time when this was considered a one-off trick, rather than one of many possible ways of playing a [[switchback]]. | |
| − | The | + | The a3 escape trick is a way to handle a 3rd row [[ladder]] approaching a red stone on a3 along the top edge. Although a3 is not sufficient as a [[ladder escape]], it can still be used as a [[switchback]], and can help Red connect when handled correctly. |
| − | + | == Example == | |
| − | + | Consider the following position, with Red to move: | |
| − | + | <hex> | |
| + | R8 C8 labels | ||
| + | blue g2 h2 e4 e5 | ||
| + | red a3 g3 f5 e6 | ||
| + | </hex> | ||
| − | + | The a3 escape trick consists of laddering to e3 (making a three-hex gap between the ladder and a3) and then connecting to a3 through a [[bridge]]: | |
| − | + | <hex> | |
| + | R8 C8 labels | ||
| + | blue g2 h2 e4 e5 | ||
| + | red a3 g3 f5 e6 | ||
| + | play numbered f3 f2 e3 e2 b4 | ||
| + | </hex> | ||
| − | + | Blue's only working response is d3, to which Red responds with another bridge: | |
| − | + | <hexboard size="8x8" | |
| + | coords="show" | ||
| + | contents="B e2 B f2 B g2 B h2 R a3 B 6:d3 R e3 R f3 R g3 R b4 B 8:d4 B e4 R 7:c5 B e5 R f5 R 9:d6 R e6" | ||
| + | /> | ||
| − | Blue can | + | No matter what Blue plays, Red can either connect with the ladder or directly to the bottom. |
| − | This escape does not always work, | + | Blue can also play c3 instead of d3 but the outcome is the same. If Blue plays d1 instead of d3, Red d3 wins locally (i.e., in this case, Red doesn't even require a connection to e6). |
| + | |||
| + | This escape does not always work, as it depends on the [[Board size|size of the board]] and the pieces already on it. | ||
| + | |||
| + | == See also == | ||
| + | |||
| + | * [[a3 opening]] | ||
| + | * [[Ladder]]s | ||
| + | |||
| + | [[category:ladder]] | ||
Latest revision as of 00:56, 16 March 2022
"A3 escape trick" is an older name for the a3 switchback. It dates from a time when this was considered a one-off trick, rather than one of many possible ways of playing a switchback.
The a3 escape trick is a way to handle a 3rd row ladder approaching a red stone on a3 along the top edge. Although a3 is not sufficient as a ladder escape, it can still be used as a switchback, and can help Red connect when handled correctly.
Example
Consider the following position, with Red to move:
The a3 escape trick consists of laddering to e3 (making a three-hex gap between the ladder and a3) and then connecting to a3 through a bridge:
Blue's only working response is d3, to which Red responds with another bridge:
No matter what Blue plays, Red can either connect with the ladder or directly to the bottom.
Blue can also play c3 instead of d3 but the outcome is the same. If Blue plays d1 instead of d3, Red d3 wins locally (i.e., in this case, Red doesn't even require a connection to e6).
This escape does not always work, as it depends on the size of the board and the pieces already on it.
