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Archive for the ‘flawed openings’ Category

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 »

FW rethought: Kissing

Posted by nand on December 17, 2009

OK, so I’m trying to rethink my approach to this, in part because there are some good midlevel players who still insist on using it despite its evident weakness. (It can win big against low- or midlevel players, I’ll admit; I’m purely concerned with optimal play, though.) Anyway, the most formidable of the “kiss” variants is one where violet tries to use Y and then Z5 or (better) T5 to round the corner, killing off all orange’s useful corners in the bottom left. Here’s the start of my line against it:

Moves: 1. F – X / 2. W – N / 3. Y – F / 4. X – W. Note that it’s a good idea to hang on to Y as a last-ditch block in the midgame (I1uur), though if it becomes freed up then it’s a major threat on top (L14ddl).

If violet is so foolish as to play N on top rather than X then you get one of my favourite positions, eminently winnable for orange:

Moves: …. 4. N – Z4 / 5. T5 – I5. This is an elegant example of an unblockable leak, since the only block (V5[F14ddr]) produces a horrendous I2-T4-I3 series of holes. You can see the violet T5 “corner kill” in action here — not that it does him much good.

If violet plays T5 on move 4 (or Z5) it’s a different line, I still think bad for violet. Will unpack it later on…

Posted in flawed openings, FW, openings | 3 Comments »

(rejected) FW: complete solution, part 1

Posted by nand on October 16, 2009

Considering all the depressing news I usually post about hard-to-beat openings, I thought it time to post something on an eminently defeatable opening. Sometimes I have a little trouble with it, so I thought it worth trying to work out a solution in more detail to avoid mistakes. As always in duo, even bad openings can win if you make a single error in your defence…

So: FW, the favourite of beginning & some mid-level players. It’s an interesting opening in that it looks pretty good but is actually one of the flimsiest of the F openings. I think this can actually be defeated by orange in ALL cases, though I must confess that I haven’t (inevitably) worked it all out. I would be very interested to hear from people who have suggestions for lines I should examine in more detail.

*****

UPDATE: I’m no longer happy with the line given below, as I think violet has a strong reply to the orange Z5. I will try to post more shortly. I will keep this page here nonetheless as an interesting false start.

*****

Here’s the basic orange response:

FW basic opening

Violet must reply on the left. (If violet plays on the right, orange plays I5(D7u) and the game is easy: I won’t spell out that line here as it should only require basic understanding of duo strategy.) There are basically two possible replies: a hang or a kiss. My solution is simple: if it’s a hang, play Z5(K8ullu); if it’s a kiss, play F(K8uul). I’ll consider the various cases in turn.

Case 1a) Hang and circle

The usual pieces for the violet hang are Z5(E7lddl), T5(E7ldd) or N5(D9ddld or dldd). If violet circles, orange should keep going aggressively rather than block until violet pokes up around the side. Here’s the line:

FW with a Z hang, the circling game

Note that orange F grabs the V in the nook of the violet F (& note that orange Z4 is dependent on keeping the W for a block). This game should produce an orange win of about 3 points. If violet plays T5 not Z5 then orange needs a different path, playing W(A8urur) to grab the L4 spot in the nook and using a different blocking method on the right (you figure it out).

If it’s an N hang, then it’s a little trickier, but the I5 is still the best bet, I think. At worst it’s a tie but here’s my packing for a 3-point win:

FW with N hang, orange I5

Moves: 1. F – X / 2. W – N / 3. N – Z5 / 4. Z5 – I5 / 5. I5 – T5 / 6. T5 – F (very important to tee up the I3!) / 7. L5 and the rest is hole-filling and packing.

Or if you like to make things exciting this is a good line too, & possibly a larger win (I haven’t worked it out in full but in practice it can lead to bigger wins versus players who aren’t good with open games):

FW with N hang, circling

Posted in flawed openings, FW, openings | Leave a 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 »

Achilles heels #2

Posted by nand on June 1, 2009

This is a favourite of newbies, but it’s not very strong versus a player who knows the trick. Basically, despite the obvious temptation for orange to play on the bottom on move 2, DON’T DO IT. Be more patient, & set up the nice 1-3-2 series of holes off the central N. This is my invariable response when violet tries to circle round the bottom, & if it’s played right then it usually wins.

A weak opening... note the 1-3-2 series of sides available to orange in the centre

A weak opening... note the 1-3-2 series of sides available to orange in the centre

Note that orange’s main concern here is that if violet’s attack persists below, then if orange keeps circling above he will start to mess up his own trap laid for violet (the 1-3-2 series) by moving into that area. It’s essential to prevent this from happening by keeping a distance between the attacks & by blocking violet’s progress below before it gets too serious. And it’s important not to give violet the opportunity to block the leak in the centre before orange can play the 1.

If violet blocks on top rather than playing the Z5 this can be trickier for orange, but usually at worst it’s a 1-point loss for orange.

Posted in flawed openings, openings, XN in centre | Leave a Comment »

Quasi-mirrors

Posted by nand on May 24, 2009

There are several openings which are worthless because of symmetry rules: orange can simply mirror every move of violet’s & produce a tie (or, if violet screws up, a win). W to the centre or Z5 to the centre on move 1 are examples of mirrorable openings. The only way for violet to break the mirror is to be able to force an assymetry at the centre of the board (e.g. by occupying 3 out of 4 of the central squares).

Both of the following are what I call quasi-mirrors: it is not impossible for violet to break the mirror at this stage, but there seems to be no strong move available to violet that would break the mirror. — In the case of the N opening, the only available mirror-breaker is L5 in the centre (violet need not play this on move 2, but needs to keep the space open for the L5 move unless orange stops mirroring first). In the case of the X opening, the obvious move is F into the centre (occupying 3 out of 4 squares), but this seems weak.

Posted in flawed openings, mirroring, openings | Tagged: | 4 Comments »

Achilles heels #1

Posted by nand on May 24, 2009

The holed FY opener comes in two forms, depending on whether the Y is place running down or across. The ideal is for orange to play F or something else into the hole, allowing violet to wrap N around orange X & start squeezing from around the edges. It’s an excellent opener to play against inexperienced or midlevel players who don’t know how to respond. Unfortunately, as far as I can tell, it has a definite solution from orange’s perspective: this is the response devised by Bobby_Bob:

Looks bad for violet...

Looks bad for violet...

You also see Y for orange N, too, though I haven’t worked it out. Orange’s obvious moves are W curling around the top or bottom.  I’d advise hanging on to F, as that’s the best block on the top if violet plays W above.

If there’s an obvious flaw in the logic here, please tell me.  (The N is weak, for instance, but I fail to see a stronger move.)

Posted in flawed openings, FY open, openings | Tagged: | 5 Comments »