Duo to the Death

Blokus has taken over my life

Posts Tagged ‘blokus’

FW solution: more pieces to the puzzle

Posted by nand on January 8, 2010

OK, here’s a few more installments in my continuing battle against this opening. In my view Z5 is probably the strongest 3rd move for violet (now that I think I’ve dealt with Y-kiss). So here’s some lines that I think should do it for orange.

1. F – X / 2. W – N / 3. Z5 – F / 4. I5 – W / 5. X – Y / 6. U – L5.

…. 4. N – L5 / 5. X – Y / 6. U – P.

This is the trickiest line as orange has no combined block+attack on bottom. Here’s one possible line. I won’t spell out the moves as they follow the same pattern as above.

This is where I get uncertain. Suppose violet ignores orange F? What is orange’s best move on top? (If orange blocks the N with e.g. T4 then this is about a 4-point loss for orange IMO.) The game becomes very open, with orange having the smaller area but two leaks into violet’s area; violet has only one leak into orange’s. I THINK that this orange Y is probably the best move but would have to work it out in more detail. (The other obvious moves: turn the knob on the Y the other way; use Z4(G12rdr) for an unblockable move in anticipation of blocking on bottom right on the next turn. Probably others too.)

Posted in blokus, flawed openings, FW, openings | Tagged: | Leave a Comment »

FY open (vertical): possible line of defence?

Posted by nand on December 17, 2009

This is one of those really tricky lines for both players. No idea which player to name it after–HRF likes it but I’m not sure if it’s his originally. I have not got a surefire defence against it but can usually make life difficult for violet. Here’s the start of one line I’m working on:

1. F – X / 2. Y – N / 3. T5 – P / 4. N ….. I vaguely recall that for move 3, violet L5 to close the centre (H8rrru) is bad, but it’s not obviously bad, so I’d better actually go & prove that another time…

Obvious next move for orange is Y or L5 (I think Y) off the X — haven’t decided what’s the best orientation yet. In general, it’s vitally important for orange to play through the hole the moment he gets the chance — it’s too soon this turn, but I would recommend it on the next turn no matter what. The trick is to avoid messing up the nice 1-2 leak off the top of orange P by letting violet block both leaks simultaneously.

Posted in FY open, openings | Tagged: | 1 Comment »

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).

Posted in openings, XF Lerpy | Tagged: | Leave a Comment »

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).

Posted in openings, XF Lerpy | Tagged: | 1 Comment »

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.

Posted in openings, XF Lerpy | Tagged: | 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

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 »

Studies in backstepped F #4

Posted by nand on June 23, 2009

I’ve been trying to be thorough with this opening, as I wish to leave no avenue unexplored. So I’m starting with what I consider to be the weakest lines first, where orange plays X up and then plays below rather than wrapping above. (In general I think that all the wrap-below options are bad for orange.) Here is what happens if the orange line I discussed in the previous post in this series — X-Y-N — is not immediately blocked by violet.

Violet 61 - Orange 56. This is cautious play for violet yet it's a 5-point win.

Violet 61 - Orange 56. This is cautious play for violet yet it's a 5-point win.

Moves:

1. F – X
2. X – Y
3. N – N
4. Z5 – W

Two notes here. 1) I picked orange Z5 because it’s the most difficult move for violet to block (because in the following move, as we’ll see, violet decides to block, so I wanted to make life difficult for him) and because I think orange F is more useful for defense on the bottom. If someone can show me a better move here or in the following steps I’d be interested to know.

2) Violet W is key: violet Z5 looks as good or better, but it’s actually a terrible mistake. As we’ll see, we need the Z5 for the block on top, & violet W on the bottom also keeps vulnerable corners away from orange.

5. Z5 – L5

I wanted to see what happens if violet plays defensively from this point onwards. Surprisingly, the answer is that — even though it looks like the board is split nearly evenly — violet has a quite decent win in his pocket. The key from this point is for violet to hang on to the Y, as the Z5-Y combo is what seals the top (with L4, T4, or V3 equally good for capping it off)

6. L4 – F
7. T5 – I2
8. Y – I1
9. V3 – W and the rest is packing.

Final score 61-56 for violet — pretty good showing. I may have missed a slightly better packing.

Unless someone can show me a variant line I will assume that the X-Y below line for orange is a washout, & move on to other lines.

Posted in Oldmanc backstepped F, openings | Tagged: | 1 Comment »

Studies in backstepped F #3

Posted by nand on June 19, 2009

In my previous post I’d started to explore what happens if orange plays X-up then circles beneath rather than above. My general feeling is that this is bad for orange but it cannot be instantly ruled out. Orange L5 on move 3 is a bad response, as we saw, since violet can block it with impunity & win handsomely. Orange N, on the other hand, cannot be blocked without violet getting into serious trouble. With ideal packing on both sides, I believe violet still wins by 1 point: here’s my packing:

Violet 61, Orange 60

Violet 61, Orange 60


If there’s an improved packing for either side I’d like to know, as it obviously makes a huge difference in a game this close to a tie.

Moves:

1. F – X
2. X – Y
3. N – N
4. W – Z5
5. P – 1
6. L5 – Z4
7. 1 – V3
8. I2 – L4 and the rest is packing

Obviously on move 4 violet must ignore orange N & instead wrap around the right with W or Z5. I think those lines do not obviously favour either side, but need to investigate further.

The other question here is whether violet N on move 3 is good. I can’t see any other obvious move, but I may be wrong.

Posted in Oldmanc backstepped F, openings | Tagged: | Leave a Comment »

Studies in backstepped F #2

Posted by nand on June 18, 2009

This is the opening I’m currently exploring a lot, as I find it very slippery. My basic feeling is that it’s not a very good opening once analyzed carefully, but it’s got enough complexity to it that it can really throw some players for a loop (including me).

My general feeling is that orange’s worst option is X up, & that trying to go underneath violet X on move 2 rather than over the top is also bad. But, again, it’s never exactly straightforward with this opening. Anyway, I’m going to pick away at it slowly, so let’s start with lines that are obviously bad for orange, before I get to ones that may favour orange.

Final score violet 65, orange 58

Final score violet 65, orange 58

Moves:

1. F – X
2. X – Y
3. N – L5

I’m not sure that violet N is good, but I’m very sure that orange L5 is a bad response to it. At this point violet has no particular reason to continue circling: he can take a stand & count on grabbing enough points to win.

4. Z5 – Z5

Violet Z5 rather than T5: normally I’d want the T5 because of the extra corner in orange’s area, but in this case (1) this is going to be a packing game and violet needs all the extra space and corners within his own area that he can get, and (2) the Z5 is plenty threatening on its own, as orange has no clean way to block it without creating further leaks.

5. P – 1
6. L5 – P

This is my best solution to the problem of how to staunch the leak off violet Z5. If violet plays I3 or I4, then orange I4 can cut across it easily.

7. I5 – U … and the rest is packing.

Possibly there is a better solution to the packing for orange; but I’m sure that the violet packing is optimal.

So: a 7-point loss. Clearly a bad line for orange. Next question is whether it’s stronger if orange L5 is replaced with a different move (like Y or N or W)…

Posted in Oldmanc backstepped F, openings | Tagged: | 1 Comment »

Achilles heels #3

Posted by nand on June 10, 2009

One of the most popular openings is the XF kiss. People often call it the “TT” (Tetris-Time) after a player who developed it a lot (not sure if it’s original to him). Most recently it has been reexamined fruitfully by mike_yosuke. Some people tell me it’s only a 1-point win if orange plays perfectly, but I have to inspect the lines myself before I’ll vouch for that.

Fairly early on it became known that the best reply by orange is to block off the more dangerous (hanging) corner of the X with the N. On the whole I think this should be played with the 3 side DOWN. Violet’s best response is to hang an N around the N in return (a line I’ll discuss in a different series of posts, as it’s actually a pretty solid opening), but a lot of beginning and mid-level players are too cautious and play a W to kiss it, which is pretty weak if orange knows what to do. Here’s a typical game with an orange victory.

Violet 57 - Orange 68. One example of why move 3 violet W is bad in this opening.

Violet 57 - Orange 68. One example of why move 3 violet W is bad in this opening.

This isn’t the best line for violet, but I’m more interested here in showing “typical” play. If you’re a beginning player you can learn a lot from this game about how to close up apparently dangerous leaks: the I3 side on orange’s N is far less vulnerable than it appears, as violet learns to his cost.

The moves:

1. X – X
2. F – N
3. W (bad!) – Y
4. Y – Z5

note: NOT F, it’s important to save it for the bottom. And not T5, as it’s important that orange have two corners in violet’s area which cannot be simultaneously blocked by a single violet move.

Violet has by now let orange secure the bottom right corner; & orange is also now impossible to stop from grabbing some of the top right. (Violet’s Y should be turned with the knob on the left, but I’m not sure this is sufficient to save the game for violet.) From here on out, various lines are possible, none of them favouring violet.

5. Z5 – F
6. N – L5

VERY important to create the one-square “pocket” here (4 up, 4 across from the bottom corner) which will eventually stop the leak around orange N.

7. T4 – P
8. 1 – I3
9. I3 – W … and the rest of the game is just packing.

Note that the beauty of the orange N in this orientation is that if violet decides to plunge ahead with an attack rather than defend, the only way he can get very far is by wrapping L5 around it…. giving orange lots of nice long sides to work with (& meanwhile orange’s smaller area is eminently defensible with all its jagged corners).

Posted in flawed openings, openings, XF Tetris-Time | Tagged: | 3 Comments »