Difference between revisions of "Tom's move"

Revision as of 06:03, 9 December 2020

Introduction

Tom's move is a trick that enables a player to make a connection from a 2nd-and-4th row parallel ladder. It can also be used to break through a 2nd row ladder using a single stone on the 4th row, or to connect a single stone on the 4th row to the edge. Its name originates from Tom Ace (player Tom239), who devised it during a game against dj11, on 15 December 2002 on Playsite. This was not its first use ever, just how it came to be known among Hex players on Playsite.

Example

In this diagram Red wants to connect to the bottom edge.

It looks impossible to use the single stone on the 4th row as a ladder escape. How can it be done? By using Tom's move:

Red pushes the ladder until she is right underneath it, and then she plays at 5.

Why Tom's move is connected

Red has three main threats:

using the ziggurat and

where the group containing 1 is connected to the left via one of the spots marked with + and trivially to the bottom.

The overlap in which Blue has to play:

The 4 different moves are now considered one by one.

If Blue moves at a:

The group containing 4 is now connected to the bottom via the template III-2-b

If Blue moves at b:

  The group containing 4 is now connected to the left by one of the threads marked with + and to the bottom via the template IV-2-b

If Blue moves at c:

If Blue plays 3 before 5, Red can play 4 before 6.

If Blue moves at d:

So all of Blue's blocking attempts fail.

See also

• 2nd and 4th row parallel ladder escape