Difference between revisions of "Edge template V1a"
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=== Red's threats === | === Red's threats === | ||
| − | Reduction to [[ | + | Reduction to [[edge template III1b|template III-1-b]]: |
<hexboard size="5x10" | <hexboard size="5x10" | ||
visible="area(a5,c3,d3,f1,h1,h2,i2,i3,j3,j5)" | visible="area(a5,c3,d3,f1,h1,h2,i2,i3,j3,j5)" | ||
Revision as of 21:44, 20 June 2021
Template V1-a is a 5th row edge template with 1 stone.
This template often appears as a third move, for instance in the a3 opening, because the played piece is guaranteed to link to one edge and is not too far from the other one. Thus it follows the principle of the weakest link.
Note that there is also a mirror image form of this template.
It may seem that this template is very strong because it reaches 5 rows into the board, but it rarely occurs outside of the opening, because of the huge size of the template; the template requires 31 empty hexes and 10 hexes along an edge — the entire edge on the 10x10 board!
Furthermore, the large perimeter makes it more vulnerable to encroaching adjacent plays and forcing moves. Additionally, the carrier surrounds the 5th row piece on both "shoulders" so that non-overlapping plays from the 5th row piece can occur in only two directions.
Contents
Defending the template
Red's threats
Reduction to template III-1-b:
Reductions to template IVa:
Reductions to template IVb:
Blue's options
These threats only overlap in 3 hexes, so to attempt blocking the template, Blue must move in one of these.
If Blue moves at x:
Red responds as follows.
Red is threatening to connect at "+". Blue must block by playing somewhere between Red's two pieces. Red then continues as follows:
Red has forced a bottleneck, resulting in a 2nd row ladder. Red's 2 acts as a ladder escape. The final position is
If Blue moves at y:
Red's best response is to bridge to 2. To stop the threatened immediate connection, Blue must block at 3 or intrude on the bridge. If Blue plays at 3, Red plays the following sequence of forcing moves:
Red is now connected to the edge by double threat at the cells marked "+". If Blue intrudes on the bridge instead, play proceeds similarly:
Again, Red is connected by double threat at "+".
If Blue moves at z:
Red's best response is 2, which is connected to the bottom and forms a loose connection with the Red's piece on the 5th row. To stop the immediate connection, Blue must play at a or b.
If Blue moves at a, Red plays the following forcing sequence, connecting by double threat at "+".
If Blue moves at b, Red plays the following forcing sequence, again connecting by double threat.
