Edge template VI1a

Template VI1-a is a 6th row edge template with one stone.

This template is the first one stone 6th row template for which a proof of validity has been written out. The template has been verified by computer, and also verified to be minimal.

Elimination of irrelevant Blue moves

Red has a couple of direct threats to connect, using smaller templates. Blue must play in the carrier of these threats in order to counter them. To prevent Red from connecting Blue must play in the intersection of Red's threats carriers.

Using the parallel ladder trick

6 moves can furthermore be discarded thanks to the Parallel ladder trick. Of course, symmetry will cut our work in half!

We can dispose of 3 moves on the left (and, using mirror symmetry, the corresponding 3 moves on the right), as follows:

At this point, we can use Tom's move as follows:

Remaining possibilities for Blue

Blue's first move must be one of the following:

See Template_VI1/Intrusion_on_the_3rd_row, Template_VI1/Intrusion_on_the_4th_row, Template_VI1/The_remaining_intrusion_on_the_fifth_row.

Specific defense

For the moves that intersect all the carriers, Red has to find specific answers. Let's deal with the remaining intrusions!

One remaining intrusion on the first row (stub)

Details to follow

The other remaining intrusion on the first row

Red should go here:

See more details here.

The remaining intrusion on the third row (stub)

Red should go here:

Details to follow.

The remaining intrusion on the fourth row

Red should move here (or the equivalent mirror-image move at "+"):

For more details, see this page.

The remaining intrusion on the fifth row

First establish a double ladder on the right.

Then use Tom's move: