Difference between revisions of "Cornering"
(→D3 corner move: Showed a more logical sequence of moves for d3 corner move.) |
(add katahex-approved sequences; also, in the last c4 corner move example, Blue 6 is actually not a bad move) |
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| Line 40: | Line 40: | ||
B 6:e5 R 7:f6 B 8:e6 R 9:g3 E *:f5 *:h4 B 10:e4 R 11:f2" | B 6:e5 R 7:f6 B 8:e6 R 9:g3 E *:f5 *:h4 B 10:e4 R 11:f2" | ||
/> | /> | ||
| − | Note how Red's 9 is connected to the edge via a [[double threat]] at the cells marked "*". If Blue instead plays 6 on the second row, | + | Note how Red's 9 is connected to the edge via a [[double threat]] at the cells marked "*". If Blue instead plays 6 on the second row, the position transposes to one commonly encountered with the D3 corner move (described below). |
<hexboard size="7x8" | <hexboard size="7x8" | ||
| Line 67: | Line 67: | ||
/> | /> | ||
This move has some similarities with [[Tom's move]], although it does not require a [[parallel ladder]]. Note that 5 and 9 are connected to the edge by [[edge template IV2b]]. The shaded area is not required for this move, i.e., it can be occupied by Blue. | This move has some similarities with [[Tom's move]], although it does not require a [[parallel ladder]]. Note that 5 and 9 are connected to the edge by [[edge template IV2b]]. The shaded area is not required for this move, i.e., it can be occupied by Blue. | ||
| + | |||
| + | However, KataHex more commonly prefers the following Red 7, followed by move 9 at one of (*): | ||
| + | <hexboard size="8x9" | ||
| + | coords="hide" | ||
| + | edges="bottom right" | ||
| + | contents="R a7 B a8 R 1:b7 B 2:b8 R 3:c7 B 4:c8 R 5:f6 B 6:e7 R 7:g4 B 8:e6 E *:(f5 h2)" | ||
| + | /> | ||
| + | |||
| + | If there are no nearby stones, both moves often result in Red climbing towards the center. For example: | ||
| + | |||
| + | <hexboard size="8x9" | ||
| + | coords="hide" | ||
| + | edges="bottom right" | ||
| + | contents="R a7 B a8 R b7 B b8 R c7 B c8 R f6 B e7 R g4 B e6 | ||
| + | R 9:h2 B 10:d5 R 11:e3 B 12:c4 R 13:c5 B 14:d4 R 15:d2" | ||
| + | /> | ||
| + | |||
[[category:ladder]] | [[category:ladder]] | ||
[[category:definition]] | [[category:definition]] | ||
Revision as of 17:45, 29 April 2023
In a ladder situation when no ladder escape exists, the attacking player can ladder into a corner and create a "quasi-escape piece" at the very last minute. This play is called cornering.
Pivoting
The most common form of cornering is pivoting: when the attacker breaks the ladder by playing one hex ahead. This usually results in a ladder for the opponent. Example:
This results in a new ladder, but now the attacking player is defending instead.
Red could have also cornered earlier, resulting, for example, in a 4th row ladder for Blue.
C4 corner move
Given enough space, the attacker can sometimes get an outcome that is better than merely turning the ladder, though not as good as a switchback. For example, starting from a 2nd row ladder, the following maneuver lets Red move towards the center, rather than parallel to Blue's edge:
Blue now has several options, but all of them allow Red to connect towards the center of the board:
Note how Red's 9 is connected to the edge via a double threat at the cells marked "*". If Blue instead plays 6 on the second row, the position transposes to one commonly encountered with the D3 corner move (described below).
Note that Red's 7 is connected to the edge via edge template IV2b.
D3 corner move
Another useful corner move for second row ladders is this:
This allows the attacker to climb to "*", even without a switchback threat, as follows:
This move has some similarities with Tom's move, although it does not require a parallel ladder. Note that 5 and 9 are connected to the edge by edge template IV2b. The shaded area is not required for this move, i.e., it can be occupied by Blue.
However, KataHex more commonly prefers the following Red 7, followed by move 9 at one of (*):
If there are no nearby stones, both moves often result in Red climbing towards the center. For example:
