Serial moves to selfsacrifice December 26, 2007
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The series helpmate is an unusual and fascinating problem form. In it Black executes a series of moves, that all have to be legal, while White does nothing. Finally White gets to make a single move, and mates Black with it.

Let us take a look at an example used by Andrew Martin in his Radio ChessBase lecture last January. It is a problem composed by N. A. McLeod:

Series helpmate in six

Once again the exact stipulation: Black must make six consecutive moves, all of which must be perfectly legal. For instance he cannot put the white king into check, except on the last move, and he cannot allow his own king to move into check. White does nothing, until after six black moves he plays one move to deliver mate.

In the above position it is clear that the final move will be Bg2# mate. Black has six moves to place his pieces on squares where they cannot defend against the mate from g2. Naturally one black piece may be captured, but just one, on the final move.

When we examine the above position we see that the black bishop on e8 cannot remain there, since it would defend against the Bg2 mate. However, removing it means that there cannot be a black rook or queen on the eighth rank, because otherwise they would be checking the white king, which would be illegal during the first five moves. If it occurs on the sixth move the final mate could not be delivered.

If the rook and queen cannot be on the eighth rank, where can we put them? The black rook has only two squares where it is helpless to defend against the ultimate Bg2#, and those are a1 and h1. The queen has only one square: a1. So it is obvious where these pieces have to go. The black bishop has no square from which it cannot defend against the mate, and so it will have to sacrifice itself on g2. Thus we know what the final two moves are going to be: bBg2, wBxg2#.

How do we rearrange the other pieces. After the above analysis this becomes fairly obvious: 1.Qh8, 2.Qa1, 3.Rh8, 4.Rh1, 5.Bc6, 6.Bg2 Bxg2#. That is the correct solution. Note that in helpmates of any kind (i.e. problems in which a mate is constructed with both sides cooperating) it is always Black who makes the first move and who gets mated in the end. This leads to somewhat unusual notation, with the black moves given first and then the white move, but one has to get used to it. There are too many beautiful helpmate problems to change everything around to White moving first and getting mated.

One more thing to note is that in helpmates the order of moves is absolutely critical. If two moves could be interchanged the problem would be quite worthless. In the above example the queen has to move first to make way for the rook; then the rook has to move to h1 to avoid an illegal check on the white king, and only then can the bishop move to get to its final square.

Now we present you with two quite charming series helpmates. The first is very simple:

E. Bartel and A.H. Kniest, 1965

Series helpmate in four

So Black moves four times in a row and then White plays one move to mate him. Even an amateur should be able to solve this in a reasonable amount of time. Since we have receive a lot of letters (well, some letters... actually two readers wrote) complaining that our December 25th 2007 puzzle was way too easy. So here is a slightly harder one.

J.M. Rice, 1970

Series helpmate in eight

Do try to solve this puzzle. You will be quite enchanted (we were) when you finally discover how it all works out. Remember that the white king must never be put into check, and each move has to be unique and executed in exactly the correct order for the problem to work. Quite amazing how positions can be constructed to actually fulfull these strict conditions.

The solutions to all puzzles will be published at the end of the series (after January 1st).
Please do not send in solutions after each problem is published.