## Friday, June 13, 2008

### Grasshopper

The Grasshopper, (German Grashüpfer, French Sauterelle), is a popular fairy piece, which was invented in 1912 by the British founder of the Fairy Chess Thomas Rayner Dawson.
The Grasshopper, which in diagrams has the symbol of an upside-down Queen and in texts the letter G, belongs in the category of the hoppers. It moves on a line or diagonal (just like the Queen) towards a piece (obstacle or hurdle) and steps down on the the square exactly behind the hurdle.
If the Grasshopper is on a8 and there is another piece on a2, the Grasshopper can move to square a1. If there is an enemy piece on the arrival square, the Grasshopper captures it. The piece on a2, which were used as a hurdle for the hopping of the Grasshopper, is not affected. If there are no hurdles for the Grasshopper to jump over them, (or the Grasshopper 'sees' on its lines of movement various pieces, but they have behind them other pieces, having same color as the Grasshopper), the Grasshopper cannot move.
The Grasshopper is a linear piece strategically interesting. We can interpose on a5 a piece and the Grasshopper Ga8, which were threatening the square a1 using as hurdle the piece on a2, now is threatening the square a4 because it can hop over the piece on a5. Also, a battery with a Grasshopper is not firing after removing the front piece , but it is formed and fired by placing in front of the Grasshopper a piece.
If there are Grasshoppers in the initial position of a problem, then a pawn may be promoted to Grasshopper.

 (Problem 106) T. R. Dawson, British Chess Magazine, 1943 Mate in 2. (Grasshoppers). #2 (6+8) 1+3 grasshopper [8/7p/7K/1g2Sbp1/G3g1Sk/2B3gp/8/6s1]

The Grasshopper Gb5 is threatening Bf5.
The Grasshopper Ga4 can move to c6 and f4.
The Grasshopper Ge4 can move to e6 and g6 (not to h4).
The Grasshopper Gg3 can move to b3 and d6 (not to g5).
The Grasshopper Ga4 keeps the Ge4 pinned because, if Ge4 is lifted, then Ga4 is threatening Kh4 which is exactly behind the hurdle Sg4.

There are some tries: {1.Bxe4? [2.Be4~#] Se2!}, {1.Sf3+? Sxf3!}, {1.Sg6+? hxg6!}, {1.Sh2? Gxf5!}, {1.Gf4+? gxf4!}.

Key: 1.Se3!
It so happens that the key unpins Ge4 (!), but black is in zugzwang.
In the next three variations white forms a battery arriving on the line of Ga4, and removing at the same time the hurdle of the black G which has moved but it cannot come back!
1...Ge6 2.S5g4# (if Ge6xg4 is played, the Grasshopper from e6 becomes the hurdle for Ga4).
1...Gg6 2.Bg4#
1...Ge2 2.S3g4#

Other variations:
1...Sg1~ 2.S(x)f3#,
1...Gg3~ 2.Be1#,
1...h2 2.Sg2#,
1...Gxf5 2.Sxf5#,
1...g4 2.Gf4#.

In the next problem-147, by the IM Harry Fougiaxis, we observe in the two solutions similarity of movements on the file or on the diagonal (orthogonal-diagonal echo), where the black Grasshoppers win the needed tempo with the key:

 (Problem 147) Harry Fougiaxis 434 Sinfonie Scacchistiche No. 91-82, 06/1988 Helpmate in 2, two solutions h#2, 2.1.1.1, (5+5), 2+2 grasshopper [4G3/G7/2K1S3/2S5/3ggp2/3pk3/8/8]

By examination of this position, we locate two sequencies of moves in the set play:
1...Sg5+ 2.Ge2 Se4# (First check is discovered and the mate is made with double checking).
1...Sb3+ 2.Gf2 Sd4# (Similar mechanism with the previous one, but on the diagonal).

Look now where black will find the move to win one tempo:
1.Ge7! Sg5 2.Ge2 Se4#
1.Gb6! Sb3 2.Gf2 Sd4#

(This post in Greek language).