Chess Online

Bonus Socius, 1350

It looks easy, but it is pretty tricky

@sampotarmo

If 1. Kc2/Ke2 => Nf7 - which makes a mate on the next move impossible, because then:

Either 2.Ra8+ Kc7/d7/e7
Or 2. Rh8+ Nxh8

I agree with prinsallan. The first move was useless.  

zugzwang
aint it

Sid- I just stated that IF it was a real game, that is what I would have played.

i.e. forcing Black to move K or N and thus allow mate in 2...?

In order for a position to be zugzwang, if "black" did nothing, they wouldn't lose. In this case, doing nothing loses, so it isn't zugzwang. There are even positions of mutual zugzwang, where whoever moves loses.

One of the more common examples of mutual zugzwang is:

White has a K on g5 and a Pawn on f4
Black has a K on e4 and a pawn on f5.

Whoever moves, loses.

I fell for the Ke2 and overlooked the Nf7. Good puzzle. I wonder how many won games I lost because I miscalculated just like I did in this puzzle.

Sorry to disagree but this is an example of zugzwang. Once the rook is moved to g7 black is forced to move to a position which will result in mate. If he didn't have to move white can't mate.

As previously explained Nf7 thwarts whites chance to mate in 2.

I really appreciated it.

Move Rook as first suggested, black has opportunity to push kight to c8, then white can't checkmate in next move. Puzzle is inaccurate in description.

Yes, the description does say a forced mate, in two moves.

And the description is correct.

If one side can force checkmate regardless of what moves his opponent plays, there's a forced mate.

Any other definition doesn't make sense to me.

I agree with @eugen1943, this is a zugwang position after the first white's move.

No matter what move black does it worsen its position, and leads it to a checkmate.

By the way, nice puzzle and a little bit tricky!

Also, note the date of the problem, 1350. Kings, rooks and knights moved then as they move now. Everything else moves differently now.

If 'Forced Mate' means that there is no move that the opponent can make that prevents, or even delays, the checkmate, then this is not a 'forced mate in two'. There are 4 places that Black can move the knight to that delay the checkmate by at least 1 move.

On a different note, I believe that "en passant" is the term used in the following situation.
1) person has pushed pawn the 2 spaces (jump position 1 --> not sure on that term) and lands it beside an opposing color pawn.
2) opposing color pawn can be pushed diagonally under that just moved pawn, "en passant", and remove that pawn.

Ex. white moves pawn from a2 through to a5 (in several moves obviously). black then moves pawn from b7 to b5 (in one move), then white can 'en passant' and move pawn from a5 to b6 and take the black pawn off of b7.

Zugzwang means that if Black didn't have to move, black wouldn't lose.

Here, Black would lose even if he could "pass" after 1.Rg7! White would play 2.Rg8+, Ne8 3.Kd4 (if we continued to argue that Black could just "pass" on his moves, 3.Ra8+ would be enough), Kc8 4.Rxe8#.

BUT, it's not mate in 2 moves if Black could pass on move one. So, from a puzzler's perspective it may well be considered a zugzwang position.

I don't consider it a true zugzwang position because Black is lost regardless of whose move it is after 1.Rg7.

.. these threads as much as I do the puzzles themselves. Great stuff : )