### Analysis game #178915 human vs computer Dots and Boxes

6 replies. Last post: 2004-06-01

Analysis game #178915 human vs computer
• michael at 2004-05-26

Analysis of game <a target='new' href=“http://www.littlegolem.net/jsp/game/game.jsp?gid=178915”>#178915 human vs computer

+Opening

Since winning parity means getting even amount of chains as red (first to move) odd amount of chains as blue (2nd to move) on 6x6. I consider it a good strategy to split the board in an amount of regions equal to the ones needed to win by parity. With my moves 1, 3 and 5 i already have a good option to split the board into a top and bottom region that are sufficiently big enough to make chains. The next few moves i will try to make the regions more clear and prohibit my opponent from splitting regions.

+Move10 – midgame

I _think
here is where Knox lost the match. By moving into the top half, which was already clear to me, it leaves me the option to link bottom left and right with my 11th move. In move 20 Knox probably sees its error from move 10 and tries to split the bottom half into 2 regions by sacrificing the 2 squares in the middle. Ofcourse i saw this coming when i made move 11, and my move 15 made sure that if this move occured there would always be a 4-loop (quad) bottom left, which doesn’t count as a chain.

+Endgame

I know i won the game in parity, but as we know, dots and boxes is about the final box count. So i will make my chains as long as possible e.g move 23. Knox' move 24 puzzled me for a while, there i either leave 4 squares (2 double cross moves) to my opponent and hold on to the parity or i take 4 squares and lose parity (the last move while taking a loop is a doublecross one!). I decide to take them all which brings me 6-0 up already and move into the short chain bottom right as a pre-emptive sacrifice. Since i lose parity, i now need to try and keep his chains as short as possible. In move 26 Knox holds on to the parity and leaves a doublecross move at the end of the chain for me. Now i just peg points by trying to make a chain bottom right, which Knox cuts, but he needs to give up 2 squares again. Now my advantage in points is too big for Knox to overcome.

Knox won the parity, by sacrificing a 4-loop, and as i told many opponents already 4 points is alot if all you need is 13.

Hope this helps a bit,

michael

• Hjallti at 2004-05-29

‘Small’ question:
When you say the upper half is clear to you, does it mean you are sure to have 1 chain, or 3 in each case when reacting right to the opponent (or even 2 if you need a odd number)?

Thanks for the analysis anyway!

• michael at 2004-05-29

After move 9 the top left is a sure chain, this means that whatever my opponent tries (like giving me squares), he cannot prevent me from getting a chain there. On the top right there is nothing yet, but if my opponent wanted to split that area, he needed to give me the square in the middle, which are again extra points for me ;-)

• Knox (Computer) at 2004-05-30

I found it helpful. Note that when the board "splits"
relatively early on as it did in this game, Knox doesn’t
“know” whether this is good or bad until after the fact.
It simply doesn’t know how many regions (and of what size)
it should try to divide the board up into.

"Fox
Socks
Knox
Box

Knox in box.
Fox in socks.

— the start of “Fox in Sox” by Dr. Suess

• klaashaas at 2004-06-01

I believe I’ve read somewhere that you must always take a box if you are given the oppertunity. Is that true? If so, then why didn’t Knox do so in this game?

• michael at 2004-06-01

Yes, when there is a single box you can take, you take it, cause it cannot change anything to the outcome. I questioned Knox in the next move, and it was a human error while making the move on golem, Knox did take the square.