Defending against intrusions in template 1-Va

R5 C10 Q0 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S

Reduction to template III-1-b
R5 C10 Q0 1:SSSSS_R_SS 2:SSSS_PP__S 3:SS__PRP__ 4:S__PPPP 5:__PP_PP

Reduction to template IVa
R5 C10 Q0 1:SSSSS_R_SS 2:SSSSPR___S 3:SSPPPPP 4:SPPPPPP 5:PPPPPPP

R5 C10 Q0 1:SSSSS_RPSS 2:SSSS__PRPS 3:SS___PPPPP 4:S___PPPPPP 5:___PPPPPPP

Reduction to template IVb
R5 C10 Q0 1:SSSSS_R_SS 2:SSSSPRP__S 3:SSPPPPPP 4:SPPP_PPP 5:PPPPPPPP

R5 C10 Q0 1:SSSSS_R_SS 2:SSSS_PRP_S 3:SS_PPPPPP 4:S_PPP_PPP 5:_PPPPPPPP

Blue's choice
There are only 3 ways for blue not to fall into one of the previous reduction, we can see it if we consider the intersection of every relevant move in previous diagrams. R5 C10 Q1 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S  +f3 +d5 +f5 If Blue intrudes in the template at any hex besides the three marked '+', Red makes a move that reduces the situation to a closer template.

Solution to the intrusion at f3
The key move is the response d4. Yielding

R5 C10 Q1 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S  MH Mf3 Md4 +e2

Red is threatening to play at the marked hex which would complete the connection of the g1 piece to the bottom. Blue must block by a playing at some hex between Red's two pieces. Red then plays h2 forcing Blue to block at h3 yielding

R5 C10 Q1 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S  MH Mf3 Md4 Me2 Mh2 Mh3

Red has forced the most common pre-ladder formation. Red can get a second row ladder by squeezing through at g3 (Blue blocks at f5). Red's initial key d4 piece acts as a ladder escape which completes the connection. The final position is

R5 C10 Q1 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S  MH Mf3 Md4 Me2 Mh2 Mh3 Mg3 Mf5 Mf4 Me5 Me4

Solution to the intrusion at d5
Red's best response is to two-chain to h2. To stop the threatened immediate connection, Blue must block at h3 or play the forcing move g2 in the two-chain. The first play is defeated by the forcing sequence f4, g2, f2, f3, e3 yielding

R5 C10 Q1 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S  MB Md5 Mh2 Mh3 Mf4 Mg2 Mf2 Mf3 Me3

Red is now threatening to connect to the bottom in two non-overlapping ways, by playing e4 or by two-chaining to c4. Blue cannot stop both threats with a single move. The other play, g2 (after Red's h2) is defeated by the forcing sequence h1, h3, f4, g3, f2, f3, e3 yielding

R5 C10 Q1 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S  MB Md5 Mh2 Mg2 Mh1 Mh3 Mf4 Mg3 Mf2 Mf3 Me3

Red is again threatening to connect to the bottom in the same two non-overlapping ways: by playing at e4 or two-chaining to c4. Blue cannot stop both threats with a single move.

Solution to the intrusion at f5
Red's best response is play e4 which is connected to the bottom and forms a loose connection with the g1 piece. To stop the immediate connection, Blue must play in the middle of the loose connection at one of the hexes marked "+" in the following diagram.

R5 C10 Q1 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S  MB Mf5 Me4 Pf2 Pf3

The move f2 is defeated by the forcing sequence g2, f3, g3 yielding

R5 C10 Q1 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S  MB Mf5 Me4 Mf2 Mg2 Mf3 Mg3

Red is threatening to connect to the bottom in two non-overlapping ways: by playing at f4 or two-chaining to h4. The alternative response, f3, is defeated by the forcing sequence e2, d5, e5, e3, d3 yielding

R5 C10 Q1 1:SSSSS_R_SS 2:SSSS_____S 3:SS 4:S  MB Mf5 Me4 Mf3 Me2 Md5 Me5 Me3 Md3

Red is threatening to connect to the bottom in two non-overlapping ways, by playing at d4 or c4.

Note that template Va occurs in a mirror-image form (in the mirror image form, the three hexes on the 5th row (from the bottom) are shifted over 1 hex to the G, H, and I columns). It may seem that this template is very strong because it reaches 5 rows into the board but it rarely occurs because of the huge size of the template; the template requires 31 empty hexes and 10 hexes along an edge &mdash; the entire edge on the 10x10 board!

Furthermore, the large perimeter makes it more vulnerable to encroaching adjacent plays and forcing moves. Additionally, template area surrounds the 5th row piece on both "shoulders" so that non-overlapping plays from the 5th row piece can occur in only two directions.