Difference between revisions of "Template VI1/Intrusion on the 3rd row"
(Trying to complete the proof. The last case should be simplified.) |
(The last case simplified) |
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E a:g3 d:g4 f:f5 g:g5 k:g6 y:i4" | E a:g3 d:g4 f:f5 g:g5 k:g6 y:i4" | ||
/> | /> | ||
| − | If Blue plays at a,f or g, then Red plays at b. | + | If Blue plays at a, f or g, then Red plays at b. |
Note that Red connect down from the left by playing d, and connect down from the right by playing y. | Note that Red connect down from the left by playing d, and connect down from the right by playing y. | ||
The only way for Blue to block both is to play k, but Red with the same strategy on the left would produce a 2nd row ladder toward the right. | The only way for Blue to block both is to play k, but Red with the same strategy on the left would produce a 2nd row ladder toward the right. | ||
| Line 55: | Line 55: | ||
edges="bottom" | edges="bottom" | ||
visible="area(i1,c4,a6,o6,o4,k1)" | visible="area(i1,c4,a6,o6,o4,k1)" | ||
| − | contents="R j1 B h4 R h2 B e6 R 1:g4 | + | contents="R j1 B h4 R h2 B e6 R 1:g4 |
| − | E a:g3 b:h3 y:i4" | + | E a:g3 b:h3 y:i4 f:f5 g:g5 j:f6" |
/> | /> | ||
| − | Finally if Blue plays at i, then Red plays at d. | + | Finally if Blue plays at i, then Red plays at d. Apart from the bridges, Blue is forced to play g, and then Red plays b, forcing Blue to block on the right part (against Red y). Red then wins with f, making a capped flank on the left. |
| − | + | If Blue intrudes at a, then Red responds at b, forcing Blue to block on the right part, and then Red wins with j. | |
| − | If | + | |
| − | + | If Blue intrudes at b, then Red responds at a. Blue is still forced to play g, and then Red wins with f. | |
{{stub}} | {{stub}} | ||
[[category:edge templates]] | [[category:edge templates]] | ||
Revision as of 04:06, 20 September 2023
This article deals with a special case in the defense of edge template VI1a, namely the intrusion on the 3rd that is not eliminated by sub-templates threats.
Basic situation
In this situation, there are only 3 possible winning moves for Red, and they are "a", "b", and "c". Of these, "a" is the easiest to verify, so we will assume Red plays there.
Before continuing the analysis, we first note that Red can escape all 2nd row ladders coming from the left, as follows:
Apart from attacking the bridge, which Red defends, Blue's next move must be in the shaded blue area, or else Red plays at d and connects.
If Blue plays at c, e, h, j or k, Red responds at d and gets a 2nd row ladder, which connects. If Blue plays at b, Red plays at x and connects by edge template IV1a. If Blue plays at d, Red plays at x and gets a 2nd row ladder, which connects. This leaves a, f, g, i.
If Blue plays at a, f or g, then Red plays at b. Note that Red connect down from the left by playing d, and connect down from the right by playing y. The only way for Blue to block both is to play k, but Red with the same strategy on the left would produce a 2nd row ladder toward the right.
Finally if Blue plays at i, then Red plays at d. Apart from the bridges, Blue is forced to play g, and then Red plays b, forcing Blue to block on the right part (against Red y). Red then wins with f, making a capped flank on the left.
If Blue intrudes at a, then Red responds at b, forcing Blue to block on the right part, and then Red wins with j.
If Blue intrudes at b, then Red responds at a. Blue is still forced to play g, and then Red wins with f.
