Duo to the Death

Blokus has taken over my life

Archive for April, 2010

XF Rubik, two lines of defence

Posted by nand on April 6, 2010

XF Rubik is one of the two most frustrating openings to play against (the other being XF Lerpy) since (1) there are some well-mapped lines that violet can play automatically to win by a good-to-excellent margin and (2) it’s not obvious what to do to make the loss at least up-for-grabs rather than inevitable if violet is at least moderately competent (or has a memory stocked with the more common lines). Anyway, here are two lines of defence that I think were examined a year or two ago, discarded, but have been revived. Like most old/new lines they may be flawed but since the exact reasons why they are flawed are now forgotten (or were worked out by players who are no longer frequenters of the site) and since blokus strategy has gotten subtler over the years, they are definitely worth a second look. At the moment they’re having a lot of success on the site but… well, now I’ve written a post I’m expecting that they will get a little less successful.

Variant 1:

Variant 2:

The bottom one looks better, since the 1-2 series of holes created to the left of orange F is something one instinctively avoids in duo. Yet the first one does force violet to play the ugly I5 on left if he wants to stretch past it. The good thing about both of these ones is that violet F is easily cut off & so violet is tempted to defend on right on move 3, & if that occurs orange has a lot of strong moves on the left (probably Y or L5), & I think the game is orange’s to win then. But I think the circling game doesn’t look great for orange: here’s a line that works with either positioning of orange F:

(Note that if orange plans to block on the bottom on turn 4, then orange Y should probably be L5 or even a kiss move like T4 or T5. But that looks kinda suicidal to me.) Anyway, so violet’s got two perfect series of jaggies for orange to climb over, & meanwhile violet has lots of nice moves on either side: Z5 or W on bottom, L5 kiss or hang on top. Am I missing something or is this a writeoff?


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Oldmanc (backstepped) F, close-X line 1

Posted by nand on April 1, 2010

Here’s a line I’ve used a lot lately with a fair amount of success.  I think it’s probably flawed but because the flaw comes in the midgame not early on it takes a very shrewd or lucky violet player to see the problems here.

If violet blocks on the bottom this is an easy win for orange–play N on the top (F12rrur) & violet’s defence crumbles. The tricky part comes if violet instead blocks with V5(H12uurr) or T5(H12uur), because the blocking in orange’s area is really awful–you basically end up giving away at least a 4-piece &/or being forced to use the I1. That said, I think this line is worth exploring further. Orange’s continuation on the bottom is of course Z5 or T5–I think Z5 is better but have not conclusively proven this.

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