Fang: Weitere Othello Konzepte

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Greed is One of the Seven Deadly Sins

In the last section, I talked about the importance of corners. Obviously, corners aren’t available at the beginning of the game. What you really want to know next is: what other rules can I follow during the rest of the game so that I have a chance at beating more than just beginners? If you followed my advice and played a few games with some beginning and intermediate players, you may have started to notice a pattern.

Let’s take a look at a sample position:

What assets does white have in the left position? He’s got a lot of pieces, certainly. To the untrained eye, it might even look like white is way ahead (after all, white has more pieces!). But if you look more closely, while it’s black’s turn to move, white only has 2 legal moves in the above position. And what’s worse BOTH of those moves will let black have the corner shortly afterwards. From the last section, we know that that has to be bad news for white. Luckily for white – black has to play a move here. Black has lots of choices, from the absolutely horrendous G2 (giving up a corner) to B5 to E1. If black were to play B5 here, white would then play A5 or B6 (as the other 3 legal moves in the position would give away a corner).

BLACK TO PLAY

		That hasn’t made any progress for black and it is black’s turn to move again. What if black played A5 here instead? White would respond A6 (because black would then be threatening to take the corner by playing along the A edge if white were to play B5).
BLACK PLAYS B5	WHITE PLAYS A5

		This also doesn’t accomplish much. Unfortunately for white, black has a much better move here,E1. After E1, white STILL has the same 2 moves that lose the corner.
BLACK PLAYS A5	WHITE PLAYS A6

I like to call moves like E1 the killer move because after this the game is effectively over and it turns into a process of getting the corner in the best way and building from there. Similarly, there are often sequences of 2 or more moves that win immediately and I call those killer sequences. In Othello terminology, a quiet move is a move that doesn’t disturb the position very much. On the other hand, a loud move is a move that changes the position significantly. In fact, in the above example E1 is a Perfectly Quiet Move because it flips exactly 1 disk and it provides no new moves to the opponent (therefore it’s as quiet as any legal move in Othello can be – it doesn’t change the board very much at all). To clarify a bit more, your opponent will have the same (or fewer) moves both before and after you play a Perfectly Quiet Move. In the above example, before black plays E1, white can play to B1 and B2. After black plays to E1, white STILL can only play to B1 and B2. As a general rule, if there is a perfectly quiet move on the board it is almost always the right move to play.

BLACK PLAYS E1

What can we learn from the above position? With good play, you can force your opponent to give you corners – even if they’ve discovered how valuable corners are and they are also avoiding playing into X-squares and C-squares. The real question is: how do you get into positions where your opponent will have to give you a corner?

Let’s take a look at another example:

BLACK TO PLAY	BLACK PLAYS H6	IF WHITE PLAYED G1
Black can play the perfectly quiet move to H6 after which white can respond by playing 4 ways: H2, H3, G2, G1.	We can be pretty sure that white isn’t going to play G1 as that immediately gives black a corner.

H3 might appear good, but after H3 black can play H2 and white will be forced to play G2 or G1 – both of which lose the corner.
	IF WHITE PLAYS H3	BLACK PLAYS H2

G2 isn’t much better than H3. In fact the only way that white can try to hold on is to play H2, a dangerous (but necessary) C-square. After black plays C1 in response, white will have to play E1 or D1.
	IF WHITE PLAYS H2	BLACK PLAYS C1

White only has these 2 moves that don’t give up the corner – both are on the north edge. No matter which of these moves to the north edge that white plays next, black will play the other. If white plays D1, black will play E1, and vice versa, we call such moves paired – when the obvious response to a move is another move and vice versa. After the move pair is played out, white will be forced to give up the H1 corner on his next turn.
	IF WHITE PLAYS D1	BLACK PLAYS E1

	IF WHITE PLAYS E1	BLACK PLAYS D1

So if it’s black’s turn, white will lose. What about if it’s white’s turn? White could play H3 ,making a black move to H6 pointless (White just plays H7 after H6), however then black will just play E1 instead, forcing white to play D1 and then black will play C1 forcing white to lose a corner.

Obviously, whatever it is about the previous starting positions that is bad, it carries over no matter whose turn it is. In order to figure out how to force our opponents to give us corners, we need to figure out what features the two diagrammed positions have in common. White’s real problem in both positions is that he doesn’t really have a lot of options to begin with and the options that he has aren’t very good. When you have lots of moves to choose from you are said to “have lots of mobility”. When you don’t have many moves to choose from you are “low on mobility”. Having good mobility(having good moves) is a very important part of the game. If you have a lot of mobility – at least a few of those moves are bound to be good. And the opposite is true, if you don’t have very many moves – you might not have any good moves at all.

Many games between an expert and a beginner are decided in terms of mobility alone. The expert quickly runs the beginner out of good moves, and then forces the beginner to give up a corner (by leaving the beginner one or two moves that both lose a corner) and from there it’s all a matter of technique.

Why doesn’t white have much mobility in the above diagrams? Because black doesn’t have a lot of disks., Obviously if black only has 3 or 4 disks, white will probably have only 2 or 3 moves. If those 2 or 3 moves are all moves that give away a corner, then black is probably going to win. The point I’m trying to make here is that by having fewer disks, you can get into positions where your opponent is forced to give you a corner. Having fewer disks is actually better most of the time!

Unfortunately, this can be a very difficult lesson to learn. The “goal” of the game is to get the most disks, right? Wrong. The goal of the game is to have the most disks at the end of the game. We’ve already seen how having corners leads to stable disks and we know that stable disks lead to more disks at the end of the game. In between the start and the end of the game, our goal is to put ourselves into a position where we’re likely to have the most disks at the end of the game. If this means having fewer disks in the opening and midgame, then so be it.

Exercises:

Now that we’ve seen a little bit about how we can force our opponents to give us a corner – these exercises will help us find the killer moves that are necessary to get the job done. Find a move or short sequence that forces your opponent to give you a corner. Note that in most of these positions there are multiple answers. I’ve picked the shortest killer sequence as the answers. If you found another forced sequence, good job!	1.	2.
	Black To Play	Black To Play

	3.	4.
	Black To Play	Black To Play

Answers:

1.

2.

3.

4.

Exercises:

Find the Perfectly Quiet Move in each of the following positions:	1.	2.
	BLACK TO PLAY	BLACK TO PLAY

	3.	4.
	BLACK OR WHITE TO PLAY	WHITE TO PLAY

Answers:

1. F4 2. H5 3. C6 is a Perfectly Quiet Move for BOTH players 4. H4

Don’t leave yourself high and dry

Let’s say that your opponent is trying to maximize their disks. At some point in the game, you’re likely to get wiped out if you completely commit yourself to minimizing your disks. The term for this situation is overevaporation. Unfortunately, you can’t always focus on just minimizing your disks,you sometimes have to pay attention to make sure that you’re not going to wipe out. Remember having fewer disks is a means to forcing your opponent to give you corners, it is not an end in and of itself.

In order to avoid being wiped out by someone who is playing greedily, you’ll want to try to play moves that do 1 of 3 things (in this order of importance):

• Establish a stronghold on an edge that your opponent can’t flip
• Play a move that flips disks in more than one direction at once
• Play a move that makes a line that is not immediately reflippable.

Let’s take a look at examples of each of these in turn.

Establish a stronghold on an edge that your opponent can’t flip

Edge disks are harder to flip than regular disks as they can only be flipped by other disks on the edge, instead of in 8 different ways like all the other disks. By establishing a stronghold on the edge and not letting your opponent flip those disks, you guarantee yourself that you’ll have some disks to play off of later in the game.

		In the left example, black could play moves like E7 or E2 that immediately get wiped out. For instance, if black played E7 white would play E8. In order to avoid being wiped out, black can try to establish a stronghold on an edge that White will never be able to flip. For instance, if black were to play H5, then white can never take black off of the edge because no matter where white plays along the edge, black can just capture along the edge and protect his stronghold.
BLACK TO PLAY	BLACK PLAYS H5

		For instance, if white tries to get on the edge with H4, black will just take the edge with H3. As long as white can’t take black’s edge disks, black can’t be wiped out. Notice that in the original diagram black had several other possible edge moves (A5, H4, H7), however, H5 is the quietest move and it leaves white with the fewest options (in fact , it’s an easy win for black), and that makes H5 the correct choice.
WHITE PLAYS H4	BLACK PLAYS H3

Flip in more than one direction at once

If you are dangerously low on disks, flipping more disks will help you avoid being wiped out. That is one of the reasons that flipping in more than one direction at once is good. You tend to flip more disks when you flip in more than one direction. Also, your opponent can never wipe you out on the move immediately following a move in which you’ve flipped in more than one direction.

		In this position, establishing a stronghold on the edge by playing C8 doesn’t work because then white plays E8 and neither player has any more legal moves (and thus white wins). Obviously another idea is in order. An example safe move is for black to play B4 which flips disks in 2 directions. After this move, white can’t wipe black out during his or her next move.
Black To Move	Black Plays B4

Make a line that is not immediately reflippable

Obviously if a line is not immediately reflippable then your opponent can’t wipe you out on the next move. Making a non-reflippable line is usually a delaying tactic that you will use until you can play moves that meet one of the two above criteria.

		In the example, if it were white’s move, white would play H2 or G2 and wipe black out. Since black has no moves that establish a stronghold on an edge – nor does he have any moves that flip in more than one direction at once, black’s only reasonable moves are ones that makes a line that white can’t immediately reflip. In this case there are 2 moves that meet our criteria - C7 and G7. Obviously black doesn’t want to give white the corner so black should play C7 here. The move to C7 forms a line between C7 and G3 that white cannot immediately reflip the next turn. Now, regardless of what white lays, black will have moves like H6 and B4 next move which will avoid being wiped out.
BLACK TO PLAY	BLACK PLAYS C7

What’s in an edge

Let’s take a look at another position and see what we can learn from it:

	So you’re looking at the position and you’re wondering “OK, black has a lot fewer disks and white has very poor mobility. How does black win a corner?” The answer is: black can’t win a corner in this position (at least – not in the next couple of moves). What’s different about this position? Because of black’s disk placement, white only has one “dangerous” move that he could play if it were his turn, A2. It is very easy for white to avoid playing to A2.
BLACK TO PLAY

Let’s play fantasy Othello for a bit and move one disk on the board slightly

	Now black does have a move that wins a corner (black plays B1 and white must play B2). You should notice that in the second diagram, the disk that previously was in the middle of the board is now on the edge. In fact, in all of the winning positions that were presented in the last chapter as examples (and in the current example as well), all of the correct moves for black to play (because they force white to lose a corner) were edge moves. As mentioned in the last chapter, edge disks can only be flipped along the edge so this means that edge moves tend to be quieter than non-edge moves. Quieter moves give your opponent fewer options the next turn. Eventually if you can play enough quiet edge moves, your opponent will run out of other moves and have to give you a corner. This simple strategy is known as edge creeping because you are attempting to creep slowly along the edge until you win a corner.
		BLACK TO PLAY

Another thing that you should notice is that in the original diagram, the black disk is on the outside of the mass of white disks where it could be flipped – which means that white has a couple of possible moves to begin with. Disks that are on the outside of a mass of opposite colored disks that can be flipped are called frontier disks. The edge disk in the second example isn’t a frontier disk at the current time because it can’t be flipped. In the future, white may get a disk at D1 or black could play to D1 in which case C1 would become a frontier disk. Since every frontier disk provides your opponent with a potential move, having,fewer frontier disks mean that you have a better position.

Now that I’ve set some general guidelines, we’ll spend the next few chapters exploring the three phases of the game: the opening, the midgame, and the endgame. We’ll look at how to apply these guidelines to the three phases of the game as well as when these guidelines no longer apply.

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