Difference between revisions of "Center opening"
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| − | Playing the first move in the center | + | Playing the first move in the center would arguably be the strongest opening in [[Hex]], if the [[swap rule]] were not used. However, due to the swap rule, it is in fact one of the weakest openings. |
| + | |||
| + | <hexboard size="7x7" | ||
| + | edges="all" | ||
| + | coords="show" | ||
| + | contents="R d4" | ||
| + | /> | ||
| + | |||
| + | == Uses == | ||
| + | |||
| + | On [[Little Golem]], the center is one of the most popular openings. Presumably it is only used by weak players, or players who are not aware of the swap option. | ||
| + | |||
| + | The center opening is relatively common in [[handicap]] games. For example, in the [[Handicap#Demer_handicap_system|Demer handicap system]], a handicap of 0.5 moves amounts to playing without the swap rule. In this case, Red should open in the center. | ||
| + | |||
| + | == Strategies == | ||
| + | |||
| + | When playing a [[handicap]] game on a small board, a common strategy to defend against the center opening is to trick the opponent into connecting too strongly to one side while neglecting the other. This typically works because the opponent is inexperienced. (If the opponent were experienced, then either there shouldn't be handicap or the handicap shouldn't be on a small board). For example, on a 7×7 board, this might look like this: | ||
| + | <hexboard size="7x7" | ||
| + | coords="show" | ||
| + | edges="all" | ||
| + | contents="R 1:d4 B 2:c5 R 3:d5 B 4:e6 R 5:c7 B 6:c6 R 7:d6 B 8:d3" | ||
| + | /> | ||
| + | After Red's move 5, Blue 6 is winning. The problem is that Red did not [[minimax]]. Instead of playing move 5 at c7, Red could have played c4, which would have still connected to the bottom edge by a [[ladder escape fork]], while also connecting to the top by [[edge template IV2a]]. This would have been winning for Red. | ||
| + | <hexboard size="7x7" | ||
| + | coords="show" | ||
| + | edges="all" | ||
| + | contents="R 1:d4 B 2:c5 R 3:d5 B 4:e6 R 5:c4" | ||
| + | /> | ||
| + | |||
| + | When giving [[Handicap#Description_of_the_Demer_handicap_system|0.5 handicap]] on 11x11, if Red plays the center opening, Blue more-often tries to set up one side first, with a 2 or perhaps a "*", | ||
| + | <hexboard size="11x11" | ||
| + | coords="show" | ||
| + | edges="all" | ||
| + | contents="R 1:f6 B 2:(f3 f4 f8 f9) E *:g4 *:e8" | ||
| + | /> | ||
| + | before trying to get the opponent to connect too strongly to the other side. (There are other things for Blue to try here, but the shown 2s are most common.) | ||
| + | [[category:opening]] | ||
Latest revision as of 03:58, 13 September 2021
Playing the first move in the center would arguably be the strongest opening in Hex, if the swap rule were not used. However, due to the swap rule, it is in fact one of the weakest openings.
Uses
On Little Golem, the center is one of the most popular openings. Presumably it is only used by weak players, or players who are not aware of the swap option.
The center opening is relatively common in handicap games. For example, in the Demer handicap system, a handicap of 0.5 moves amounts to playing without the swap rule. In this case, Red should open in the center.
Strategies
When playing a handicap game on a small board, a common strategy to defend against the center opening is to trick the opponent into connecting too strongly to one side while neglecting the other. This typically works because the opponent is inexperienced. (If the opponent were experienced, then either there shouldn't be handicap or the handicap shouldn't be on a small board). For example, on a 7×7 board, this might look like this:
After Red's move 5, Blue 6 is winning. The problem is that Red did not minimax. Instead of playing move 5 at c7, Red could have played c4, which would have still connected to the bottom edge by a ladder escape fork, while also connecting to the top by edge template IV2a. This would have been winning for Red.
When giving 0.5 handicap on 11x11, if Red plays the center opening, Blue more-often tries to set up one side first, with a 2 or perhaps a "*",
before trying to get the opponent to connect too strongly to the other side. (There are other things for Blue to try here, but the shown 2s are most common.)
