Skype coaching session, 11 September 2016.

Please note: Re-structuring of the sessions now offers the option for guests 
to bring their own games for group discussion.

Recordings of some previous coaching sessions can be found at:

http://www.open-aurec.com/Skype/PaulBenson/PaulBenson.htm

The following were examined:
Two middlegame tactic problems.
Philidor's position is described.
King and rook with a bishop-file or a centre-file pawn against king and 
rook - Philidor's position achievable, Defender can draw easily.
King and rook with a bishop-file or a centre-file pawn against king and 
rook - Philidor's position not achievable, Defender can draw with precise 
play only.

Paul Benson.

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Middlegame tactic problem 1.

Black to play.
White: Kf2, Qf6, Rd8, Pa3, Pb2, Pc4, Pe2, Pe3.
Black: Kg8, Qg4, Rf8, Pc5, Pe4, Pg6, Ph6.

Solution.
Black plays, 1. ... Qh4+, forking the white queen and king. The white queen 
is pinned to her king and cannot move.
If, 2. Kg2 Qxf6, and black is a queen up.

Tactical tools and warnings.
Pin - The white queen is pinned up the f-file by the black f8 rook.
Pin - The black f8 rook is in turn pinned to the g8 king, but the black rook 
does not need to move making the white pin less effective than the black 
pin.
Fork - The black queen safely forks the white king and queen.
File vulnerability - The white king and queen are sitting on a file which 
can be controlled by an opposing rook.
Diagonal vulnerability - The white king and queen can be forked by an 
opposing queen.

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## Middlegame tactic problem 2.

Black to play.
White: Kg1, Qd3, Re4, Nd4, Pa2, Pb2, Pc3, Pf2, Pg2, Ph3.
Black: Kg8, Qb6, Rd8, Bd7, Pa6, Pb7, Pf7, Pg7, Ph6.

Solution.
Black plays, 1. ... Bf5, skewering the white rook and queen.
The white knight is pinned to the queen and so dare not capture the black 
bishop.
If, 2. Re8+ Rxe8 3. Nxf5 Re1+ 4. Kh2 Qxf2, and black is an exchange up with 
the attack on the white king to continue.

Tactical tools and warnings.
X-ray attack - The black d8 rook has an x-ray attack on the white d3 queen 
through two pieces.
Pin - The black bishop safely forks the white rook to the queen.
File vulnerability - The white knight and queen are sitting on a file which 
is potentially controllable by an opposing rook.
Diagonal vulnerability - The white rook and queen are sitting on a diagonal 
which can be attacked by an opposing bishop.
X-ray attack caution - High value units should be fearful of an x-ray 
attack, irrespective of how many interfering units are sitting between the 
attacking unit and vulnerable unit.

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## Philidor's position is described.

It is a rook and pawn against a rook.
The attacker has a pawn on a bishop-file or centre-file which has not 
advanced further than the 5th rank.
The attacking king has not advanced further than the 5th rank and is 
protecting the pawn.
The attacking rook is controlling the 7th rank.
The defending king is sitting on the promotion square of the opposing pawn.
The defending rook has access to the defender's 3rd rank.

Position with the defender (black) to play and create Philidor's position:
White: Kf5, Ra7, Pe5.
Black: Ke8, Rb1.

Black plays, 1. ... Rb6, and this is Philidor's position, learn it or lose 
it.
The black rook now controls the defender's 3rd rank, which prevents the 
white king from advancing to the attacker's 6th rank, a very important 
restriction necessary to draw.

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## King and rook with a bishop-file or a centre-file pawn against king and 
rook - Philidor's position achievable, Defender can draw easily.

From the position described above, black plays, 1. ... Rb6, taking control 
of the defender's 3rd rank and restricting the opposing king. The only move 
to make progress for white is, 2. e6.
Once white commits the pawn to the attacker's 6th rank, the black rook 
advances to the defenders 8th rank with, 2. ... Rb1, and will continue to 
harass the white king with a series of distant checks on, f1, e1, d1, 
depending on which file the white king attempts to escape. It cannot evade 
the checks - It has no shelter.
If the white king retreats toward his back rank then the e6 pawn can be 
attacked by the black rook and will soon be captured.
If white tries to block the anticipated checks with a rook retreat, 3. Ra4, 
then a drawn pawn ending can arise after. 3. ... Rf1+ 4. Rf4 Rxf4+ 5. Kxf4 
Ke7 6. Ke5. Now black must defend accurately by staying on the file of the 
white pawn.
So, 6. ... Ke8 7. Kf6 Kf8 8. e7+ Kf8 9. Ke6, stalemate.
When defending against a single pawn, the defending king must retreat and 
stay on the file of the pawn. Do not retreat diagonally, stay on the file.

* * *

## King and rook with a bishop-file or a centre-file pawn against king and 
rook - Philidor's position not achievable, Defender can draw with precise 
play only.

Again from the above position but this time it is white to play.
White advances with, 1. Kf6, and black cannot achieve Philidor's position.
If black blunders with, 1. ... Rb6+ 2. e6, white threatens a back rank mate 
with the the rook. So, 2. ... Rb8, is now forced. Then white plays, 3. Re7+ 
Kf8 4. Rh7, threatens a back rank mate again while freeing the e7 square for 
the pawn to advance. If now, 4. ... Kg8 5. Rg7+ Kf8 6. e7+ Ke8 7. Rg8+, 
white wins the black rook and the pawn will promote next move. So, the 
defending rook must not give check on the third rank if it can be blocked 
with a pawn advance.

Black must defend precisely when the white king takes the attacking 6th 
rank, preventing Philidor's position.
So after, 1. Kf6, black must play, 1. ... Re8. The rook sits on the same 
file as the pawn, it attacks it from the rear. This is the only way to draw, 
all other tries will lose. The only move for white now to try and make 
progress is, 2. Ke6. If instead the pawn is advanced to the e6 square, then 
the white king will be vulnerable to a series of checks from the black rook. 
So after, 2. Ke6, the black king must move to avoid a back rank mate. It can 
move either way and draw, but moving to the short side is recommended and 
easier to hold.
The short side is the side of the board with the fewer number of files to 
the side of the pawn. Here there are 3 files on the kingside and 4 files on 
the queenside.
With a centre pawn the defending king will find it easier to draw by moving 
to the short side. If the attacker has a pawn on the bishop-file then the 
defending king must move to the short side to draw.
So, after, 2. Ke6 Kf8 3. Ra8+ Kg7, white has difficulties in advancing the 
pawn because of the black rook sitting on the same file as the pawn. It must 
be attacking the pawn from the rear to draw.
If white tries, 4. Kd6 Rd1+, black either has a series of checks again or 
forces the white king to find shelter on the e6 square, but in doing so the 
pawn is blocked again, and black then puts the rook back on the e-file.
So white attempts to defend the e-pawn with, 4. Re8, planning, Kd7, and, 
pawn e6. Black must play precisely again with, 4. ... Ra1. The idea is to 
give repeated check again but this time across the ranks rather than up the 
files as previously shown. White can try, 5. Kd7, but now, 5. ... Ra7+ 6. 
Kd6 Ra6+ 7. Kc7 Kf7, and the white rook must run away, allowing black to 
play, Ke6 next move and the white e-pawn soon falls.

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