Saturday, March 24, 2007


Title: Hexy
Author: Vadim V. Anshelevich
License: Registration Required

I recently found the book Hex Strategy Making the Right Connections by Cameron Browne in my local library and decided to work through it. To monitor my improvement, I played many games against the computer Hex program Hexy. I had never really played Hex before and learned a lot, both from this book and from playing Hexy.

Hex is a simple abstract strategy game invented by Piet Hein in 1942. Players take turn placing stones on a hexagonal board. The objective is to form a path connecting your opposite sides of the board before you opponent forms a path connecting their two sides. Typical board sizes are 11x11 and 14x14. It easy to prove that the with perfect play, the first player can always win. However, at present, the actual winning strategy is only known for 9x9 and smaller boards.

Hexy is a nice program and plays a strong game of Hex. It has a simple interface, just click on the hex where you want to play. All of the usual features, 4 skill levels, hints, and take backs (use the up and down arrow keys) are present. One suggestion I have is to use the "randomization" option to vary the games a bit.

While Hex programs perform poorly against top human players, Hexy is one of the best. When I started Browne's book, I could not beat Hexy even on the first level. Eventually, I was able to hold my own against level two, but I never beat level three.

My biggest complaint with Hexy is that it requires registration in order to play more than 20 games. It is free, but you have to email the author for a registration code. I actually put off doing this for a long time. Instead, using process monitor, I figured out where Hexy stores the registration information in the Windows registry, in another company's namespace. Tweaking these registry keys, I could reset the counter to 20. When I finally emailed the author, he promptly responded. Still, freeware should be free.

My only other complaint with Hexy is that the largest board size is 11x11. Given that 14x14 is a standard size in human competitions, it would be nice to have this size in the program.

There are many resources on the game Hex. The wikipedia entry for Hex casts some doubts on the soundness of the strategies in Browne's book. This might explain why I was never able to beat level 3. Hex has its own wiki. The strategy articles are worth reading if you have never played before. Thomas Maarup has a great website for the more mathematically inclined. The author of Hexy has a great paper on the inner workings of his computer program.

Hex is just one of many connection games. Two that come right to mind are Y and Havannah. If you own Zillions of Games, here are several connection games which can be played within ZoG.


At 8:38 AM, OpenID Iain said...

Thanks for the tip, but I couldn't find the key. :o(

I emailed the guy about a week ago. At least there's a new Windows port of Six - a stronger Linux AI.

At 12:23 AM, Anonymous Anonymous said...

under what company name did he use? I found it listed under vanshel (his name) and the keys were 'status' and 'game counter'. When the game exits is resets them to 0. i can set them to 1, but how do you get the registry not to change them

At 7:47 AM, Anonymous Anonymous said...

how to register this? there is nothing of use under `vanshel` in registry? the author is not responding to my email..

At 8:51 AM, Anonymous Anonymous said...

Change 0x75 to 0x74 thru a hexeditor:

0001817D: 75 74

And enter any registration code you want.

At 8:50 PM, Anonymous Hexer said...

JNZ opcode to a JZ? worked for me... thanks!


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