Later Game Decision Making (3)

By | April 8, 2011

While writing first post I originally included a blurb at the end about how the idea of moving toward the center could be applied to later game decision making as well.  Eventually I decided it didn’t really fit there – that post was too long anyway – so I decided to move it to this separate post.

When discussing the early game principle of moving toward the center, one of the rationales for doing so was that there was a lot of space in the center, and it is important to stake a claim on it.  This idea of trying to claim space that is yet unclaimed is an important one, not just at the start.  If ever you find yourself in a game and are unsure of which move to make because no moves seem immediately important, you should take a step back, and try to survey the board to determine which areas have the most open and usable space.  You should then choose a move that makes you head in that  direction, or allows you to make good plays in that space later.  However, assessing which spaces are the most open and usable is not always an easy task.  In fact, how well one is able to make such judgments is one of the skills that most clearly separates players into different skill levels.  One of the tricky parts of assessing space is getting used to the fact that you can only play from the corners.  The primary blokus rule that pieces must only ever touch corner to corner means that in order to ever place a new piece, you must have a corner already on the board ready and waiting to be linked up to.  If one colour has a piece with a long edge in some zone, for example the edge of the I5, that colour doesn’t really have any claim on the zone, since it can’t play any pieces from that edge – there is no CORNER for a new piece to touch – and it also can’t play later pieces beside that edge because of the no touching side-to-side rule.

In the above image, R thought that yellow was getting too much space to itself since a lot of the action was taking place in the bottom.  R decided to try to get a piece of the yellow space by playing the I5 to get there quickly.  Unfortunately R can’t play very well to the right of this I5 because there are no corners there.  A shorter piece with more corners would have given R a better chance to play multiple pieces on the right side as well as the top.  Not only that, things get worse for R on the next turn for Y.

After playing a long piece (say the I5 as in our example) to invade some new space,  if an enemy colour manages to block one or both of the corners of that I5, the enemy may be able to claim a large portion of the zone, even though the imaginary outline of the zone seems to be predominantly the I5.

In this case, Y played the T4 to block the R I5 on the right.  Now red will have a very hard time playing in that zone – it may be completely impossible depending on how the game progresses.

Being constantly aware of the need to focus on the corners takes practice, but it is important to remember, for your opponent’s colours as well as your own.  While a piece with a long edge may seem to get you access to a far-away area, the long pieces usually have few corners, and you may end up getting no further pieces in the area you were trying to move into, especially if the few corners at the end of that piece  end up getting blocked before you play there.  Especially when moving into a new area, playing pieces with lots of corners is often more important that playing a long piece to get deep into that zone.  The long piece might get you there sooner, but it will also make it harder to play later.  A shorter piece with lots of corners may delay your play in a zone, but it can often guarantee that you are able to play more pieces in that zone anyway.

It will also be necessary later to remember that edges eat up your own space as well.  If you think you have a large corner of space just for yourself, as soon as you place a piece in it, not only do you lose all the squares that that piece takes up, but you also lose all the adjacent squares, since you are unable to play pieces in those positions.  If one of the corners you were counting on to play a piece from ends up beside an edge of your own, you will no longer be able to play the piece you were intending, and you will lose the corner.


It is sometimes the case that a player can lose all possible corners in an area, and end up not being able to play any pieces in that area, even though the area seems large, and full of the edges of the colour in question.  This kind of situation is one you should always be on the lookout for, both in your own areas, and in the areas of your opponent, in case you can play a single piece killing all of your opponents remaining corners.  The instinct to keep track of corners will become very important later when trying to come up with creative and multi-purpose blocks.  Sometimes  the amount of space a colour has can be very deceiving because of this same corner rule.

In summary:

1. Use the concept of space to help make mid-game decisions when you don’t know what to do

2. Remember that you need corners to play from, not edges – create corners when trying to access a new area

3. Be on the lookout for which corners of yours (and your opponent’s) can be easily blocked

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