Duo to the Death

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Archive for July, 2009

Studies in XF Lerpy #3

Posted by nand on July 15, 2009

With the standard version of this opening (with orange having an X, N, Y cross in the middle of the board) the tendency is for orange to be protective of the holes in his defence. This game shows that this idea may be a mistake.

XF Lerpy with orange deliberately attacking the bottom left corner

1. X – X
2. F – N
3. N – Y
4. Y – Z5
5. L5 – W
6. T4 – L4

This is the key moment in the game: violet could (& probably should) attack on the right side rather than play the T4 in the bottom left corner.

7. L4 – Z4 and the rest is packing (since orange cannot waste the 1 attacking violet’s main area, since it’s better to grab I3 in the bottom left).


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Studies in XF Lerpy #2

Posted by nand on July 15, 2009

Here’s a line I’ve played a lot as violet. It doesn’t have a happy end for orange.

XF Lerpy with orange on the defensive

1. X – X
2. F – Y
3. W – N

These last two moves are often reversed. In my view it is essential that violet play W here, even though this means that it is unavailable for the block for the leak off the orange N. Other moves here are too far away from the centre and permit orange to rob violet of too much of the corner.

4. N – F
5. Z5 – L5
6. P – W

Orange could try to take advantage of the leak off orange N here before violet has a chance to seal it off. In my experience this is a bad idea, but I suppose it could be worth a try, & I haven’t analysed it yet. — Unfortunately orange lacks any good piece for the block, i.e. one that both seals off the bottom side & maintains an attack on the bottom left corner. Te W isn’t much use.

7. V5 – Z4

Again, orange could have tried I2 off the N rather than defending, but it’s REALLY late in the day to try this now…

8. T4 – I2
9. Y – 1
10. Z4 – V3 and the rest is packing. Possibly there’s a better packing for either side–this is a screenshot from a real game, so not necessarily ideal play.

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Studies in XF Rubik #2

Posted by nand on July 8, 2009

I wasn’t entirely happy with my solution to this in the previous post (a 2-point loss for orange), though that line has the advantage of being more or less a forced game: if orange wishes to lose by only 2 points, violet really has to go along & can’t win by any more. Very useful for tournament play.

BUT: I’m not happy with that orange T5 kiss move, since it seems to me obvious that (1) it’s an unnecessary bit of finesse (since violet will not block that corner immediately) and (2) since it’s a close game & violet is really starved for spots for the 1 and i2 pieces, it’s foolish to give him those spots for free.

So, consider these screenshots as part of my continued exploration of this game, diverging at the point where I played T5 in the earlier game. I won’t give blow-by-blow lists of moves, as it’s getting late in the evening & they are mostly obvious (especially since the opening moves are identical to Study in XF Rubik #1), but I will provide comments.

XF Rubik study 2.1

One-point win for orange. Moves from L5-F on: I4-N / T4-L5 / N-I4 / V5-I3 and the rest is packing. Violet N is bad as it’s the only good block for the top — the V5 leaves an I3 hole, enough for orange to eke out a win.

XF Rubik study 2.2

I realized that the orange N in the previous game is the wrong way round, as orange needs to threaten to grab I3 AND i2 on top. So this line shows that violet can get a 3-point win this way. (If orange N is turned the right way then it’s a 2-point win for violet… I haven’t got a screen cap, but will post it later.)

XF Rubik study 2.3

So here’s another variant on the first game, with orange N in the “right” position, & orange deciding to stop the I5 (which I think is a mistake…. orange has a nice i2-1-I4 series off violet I5, & violet can’t make a really big block in bottom right off the I5 anyway). 3-point loss for orange.

XF Rubik study 2.4

A big win for orange if violet continues to circle. Violet Z5 is a mistake–should be Z4 (1 less point for violet, 2 less for orange) but anyway, this is not good for violet — the leak off the violet L5 isn’t enough to do much of anything.

XF Rubik study 2.5

This time I used L5 not F, & the results are interesting (though I have to see what it’d be like if violet blocked in top right rather than playing I4. A close win for orange, even despite the space-eating I5. (I would have to check if blocking the I5 move with P or Z4 and letting violet get I3 on top is better for orange.)

The moves from L5 on: L5-L5 / I4-T4 / T4-N / N-I3 / I5-V5 / the rest is packing.

OK, so take it from here, folks…. I want to know where these games can be improved from either side.

Posted in openings, XF Rubik | 2 Comments »

Studies in XF Lerpy #1

Posted by nand on July 4, 2009

This is one a lot of people have been asking me about. It’s a very befuddling opening for beginners, since they tend to get panicked when it looks like violet’s defences are impregnable. Even if you don’t want to learn all the possible lines, just keep these key rules in mind as orange: (1) never move into the centre on move 2; (2) try to keep nibbling at the edges of the board, keeping some corners active there. Even if you don’t win you can minimize loss by following these rules.

People on the Blokus site tend to call this opening the Lerpy, after a player (full name “lerpyfirth”) who used to use this one over & over & over until you were sick of it (he has stopped doing this, though there are other players who have taken up the baton). I don’t know whether he originally thought this one up, or someone else. — It’s a very effective opening against beginners, & can give oldtimers problems too. Its main problem is that if orange really knows the defences against it well, then it rarely wins big. But it has a LOT of different lines & it’s hard to keep them all in your head.

Anyway, here’s one winning line for orange, just to show you it can be done.

Orange 61 - Violet 60

Orange 61 - Violet 60


1. X – X
2. F – N

This is one of the standard responses. The Y up against the violet X is another standard response for move 2. If violet doesn’t move into the gap in the middle on move 3, then move 3 for orange tends to be whatever of the Y or N moves wasn’t made on move 2. That’s how this game proceeds…

3. N – Y

Orange has the option of turning the Y’s knob up for down here. I’ll discuss that line on another occasion.

4. Y – W

At this point, violet has two options: to wrap W around orange’s Y, or to play something else that’s less powerful. The reason why violet is reluctant to play the W is because it’s the only piece that can handle the 2-1 leak off the orange N.

5. L5 – L5
6. V5 – Z4
7. L4 – I2

The L4 is crucial here for violet, because violet needs to be able to seal the leak off orange Y. Otherwise orange plays the 1 off orange Y on this turn, & forces violet to ruin his packing by playing a less space-efficient piece like T4.

8. W – 1
9. I4…. and the rest is packing.

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