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Archive for the ‘XF Lerpy’ Category

XF Lerpy du jour #2

Posted by nand on October 1, 2009

Another line I’m thinking about. The orange V5 is an experiment… actually it’s not bad, 4pts loss is respectable though I usually try in “solved” lines to get it down to 3 or under. In general I want to find the key points where orange can play a defensive move without resulting in a huge loss (this is useful for tournament play).

Lerpy 1 Oct 09 game C

Moves: 1. X – X / 2. F – Y / 3. T – N / 4. W – L5 / 5. L5 – I5 / 6. N – W / 7. Z5 – V5 / 8. U – T4 / 9. Y – L4 / 10. I1 – T5 and the rest is packing.

Note if violet plays L4 for U, then orange must not use the L4 to block (it’s needed on the right). Use O4 and I2 to block–one less point, but violet also gets one less point so the results are the same.

REFLECTION: Violet Y could also be V5 (the V3 leak doesn’t matter much since orange has already left a V3 spot for himself in top left corner). Then violet gets an extra I3 but (playing through the leak) orange also gets an I3 in bottom right & the results are identical.

Posted in openings, XF Lerpy | 4 Comments »

XF Lerpy du jour #1

Posted by nand on October 1, 2009

Still thinking a lot about this opening recently — I haven’t posted much on it lately simply because I want to give genuinely useful responses (otherwise this risks simply becoming a how-to manual for people looking to win as violet by lifting games from the blog… it happens). Anyway, my suspicion is that versus good violet play it’s hard to do better than a 3-pt loss. But it’s so complex I won’t pass judgment until a lot of lines are explored.

Anyway, for the moment I’m primarily interested in what is in my view the best reply: orange Y with the knob down. So I’ll just start regularly posting games that I think are close to optimal play. If you have suggestions for where orange or violet went wrong, please post comments, as I want to really map this line out.

OK: so this line is the result of some discussion with oldmanc, who agrees with me that the orange N kissing violet F on move 3 is kinda weak. We have both toyed every so often with L5 in that spot instead. I think these games show this may be promising.

Lerpy 1 Oct 09 game A

Moves:

1. X – X / 2. F – Y / 3. N – L5 / 4. Y – Z5 / 5. T5 – W / 6. L5 – I5 / 7. I5 – F / 8. Z4 – N / and the rest is packing.

This could be improved (the screenshot is from a live game): orange plays V5 in place of N, P in place of O4, N in place of P. One point more for orange!!! But violet can also improve on it: U and 1 in place of the P, and P in place of O4. So we’re back where we started, just 62-59.

Lerpy 1 Oct 09 game B

oldmanc thought violet might do better by blocking orange I5. This game suggests the results are more or less the same. It’s a little hard to tell because both sides have to worry about leaks so packing gets tricky.

1. X – X / 2. F – Y / 3. N – L5 / 4. Y – Z5 / 5. T5 – W / 6. L5 – I5 / 7. W – I4 / 8. I5 – P / and the rest is packing (but violet must not play the O4 till orange has used up the I2, otherwise there’s a leak).

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XF lerpy: is the mirror response bad?

Posted by nand on September 5, 2009

In my initial survey of responses to XF Lerpy the first defensive response is the mirror. My instincts tell me this is not a great response, but it’s far from proven. The usual results of mirroring look like this:

XF Lerpy, P in the centre

(Moves: obviously, X-X, F-F, Z-Z, P.) Why, you may ask, does violet immediately move into the centre on move 4? This is because (1) he doesn’t want to let orange get there first and (2) he’s planning to put a nasty piece through the leak on move 5, typically V5 (J11ddrr).

That V5 caused me to dismiss this line as a disaster for orange, but after playing this out a few times I’m less certain. Basically, it’s an important demonstration of the cardinal rule in Blokus: don’t panic even if things look bad, play aggressively rather than conservatively, and keep a few corners active in as many zones of the board as possible. I played 6 games with myself using variants of this position:

XF lerpy with mirror; violet blasting through the centre

Moves: X-X / F-F / Z-Z / P-Y / V-T. I played the Y below first because it’s important to get something going in bottom left & the Y cannot be blocked in a single move. (It’s a question whether violet V5 is premature–violet could try playing W (I2urur) first, for instance.)

It’s hard to tell from playing versus myself — a live opponent may see angles I’m completely missing — but I basically tried to ensure that orange kept a toehold in all 4 corners, cut off the sides where possible, & generally just was maximally persistent & aggressive. The results were interesting: one big loss, 3 small losses, 2 small wins. That’s statistically pretty good, suggesting that though the violet V5 looks really scary this may be a viable line for orange. More to report on this once I’ve worked out some games more carefully.

Posted in openings, XF Lerpy | 4 Comments »

XF Lerpy: initial survey

Posted by nand on September 4, 2009

This is one of the most annoyingly complex openings, & tends to be regarded with exasperation by many players, largely because (1) it’s quite effective; (2) there are a LOT of mid-level players who, once they figure out that this one is pretty solid, tend to play it ALL THE TIME, game after game.  One of my major projects is to dissect this opening to the point where wins are by predictably small, rather than large, margins (rather as with the XF Rubik, XF Tetris-Time and XF Yasu, which are rarely used by experienced players versus other experienced players because the wins are so small they’re not worth bothering with). I have no idea if this opening can be ultimately reduced to a desirably small margin (in my view, 3 points or less) but it’s worth exploring at length.

I think it is worth setting out the plausible orange replies first. These aren’t all the possible replies — I’d be grateful for suggestions of any others I should examine seriously — but they are the commonest, & I think they are worth examining first before testing out others.

DEFENSIVE RESPONSES:

1. Mirror

XF Lerpy, orange mirror

2. F to the left

XF Lerpy, orange F to left

3A. N up

XF Lerpy, orange N up

3B. N left

XF Lerpy, orange N to left

OFFENSIVE RESPONSES:

4. N kissing violet F

XF Lerpy, orange N kiss

5A. Y kissing violet X, knob up

XF Lerpy, Y kiss with knob up

5B. Y kissing violet X, knob down

XF Lerpy, Y kiss with knob down

*

My current thoughts: Mirror (#1) is demonstrably bad, as I will show in a future post. F to the left (#2) is extremely effective against low- to mid-level players, but has fatal flaws that can be exploited by good players; it may nonetheless be worth exploring. N up (#3a) has a major vulnerability (violet can wrap Z5 around the orange X) but may be OK; N left (#3b) I am not very familiar with.

The major lines are #4 and #5A/B. My suspicion is that #4 is not good, because violet simply lays down N (B7drdd) and orange has no corners to work with in the bottom left corner. Thus #5A and B are the best options, the major branches depending on whether violet plays through the hole on move 3 (typically with T5, though V5 is an option) or blocks the Y.  If violet blocks the Y then orange has the option of playing the N in the same way as in #4, or playing something else there (typically T4).

I’ll try to pick away at these openings one by one, though it’s a tough job. Anyway who wants to help out, be my guest 🙂 ……

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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

Moves:
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

Moves:
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 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

Moves:

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.

Posted in openings, XF Lerpy | Tagged: | 3 Comments »