Additional punch

From the previous post:


Additional punch
Your moves must have an additional punch. An example of an additional punch is:

• a duplo attack
• an attack against an immobile target
• a desperado
• an intermezzo move

Moves with no additional punch can be pruned from the tree of analysis.

Hypothesis:

All moves in the main lines in the past few posts obey to this rule. Both yours as the opponents' moves must have an additional punch. The moment your opponent can't keep up and he is left with only moves without an additional punch, he will lose wood or he will be mated.

This means that we have here a gigantic pair of pruning shears which will be able to prune the tree of analysis in a drastical way. Before I'm going to investigate this hypothesis, I must elaborate on the term additional punch a bit more.

Duplo action move 
Duplo attack is too limited, since it only is about the function of attacking. Duplo action is a much broader term, which comprises defensive moves too.

Definition: a duplo action move is a move that requires at least two actions or one duplo action move from the opponent to answer.

Immobile target
A target can be immobile in a few different ways:

• due to lack of space
• due to a function that cannot be abandoned

The immobility makes that the opponent needs at least one extra action to free himself. Only a duplo action move can free him without the loss of a tempo.

Desperado
A desperado action is usually a capture with an additional threat. In fact it is a duplo action move. The opponent needs a duplo action move to answer:

• The desperado must be recaptured
• There must be an additional threat

Otherwise the opponent loses a tempo.

Intermezzo
An intermezzo move is, just like the desperado, just another instance of a duplo action move.

Lets have a look at the first diagram of the past posts.

Diagram 1. Black to move

r3k3/p4p1p/4p1r1/2p1n3/4nN1Q/P1PqP2P/3B2P1/2R2R1K b q - 1 1

[solution]

1. ... Ng3+

• action 1: check
• action 2: attack rook

2. Kg1

• action 1: save the king
• action 2: loses a tempo

2. ... Qxd2

• action 1: capture the bishop
• action 2: loses a tempo

Notice that black can afford to lose a tempo when white does so first

3. Nxg6

• action 1: take a rook
• action 2: threaten mate

3. ... Qxe3+

• action 1: check
• action 2: defend the knight

4. Kh2

• action 1: save the king
• action 2: lose a tempo

4. ... Nxf1+

• action 1: take a rook
• action 2: check

Notice how white can't keep up in move 4.
Notice how the threat of black's move 1 is executed with tempo

5. Rxf1

• action 1: take a knight
• action 2: lose another tempo

the final blow
5. ... Nxg6
action 1: capture the knight
action 2: defend against mate


Let's have a look at the penultimate diagram.

Diagram 2. White to move

r3rbk1/1p3ppp/2pn1qn1/p2p1b2/P2P3P/2PB1NB1/1PQNRPP1/4R1K1 w - - 1 1

[solution]

1. Rxe8

• action 1: capture a rook
• action 2 and 3: duplo attack against bishop and king

1. ... Rxe8

• action 1: capture a rook
• action 2 and 3: defend against duplo attack against bishop and king

2. Rxe8

• action 1: capture a rook
• action 2 and 3: duplo attack against bishop and king

2. ... Bxd3

• action 1: capture a bishop
• action 2: threaten queen

3. Rxf8+

• action 1: capture bishop
• action 2: check

3. ... Kxf8

• action 1: capture rook
• action 2: lose a tempo

The final blow
4. Qxd3

An earlier diagram

Diagram 3. White to move

3r2k1/5p2/1p5p/p1qb4/5R2/P1N1p1P1/1P2P2P/2Q3K1 w - - 1 1


[solution]

Let's look first at the branches that can be pruned.

1. Rg4+
Since the black king isn't immobile, the attack peters out.

1. Rf5
It is a duplo attack, but since the bishop isn't B.A.D. (Barely Adequate Defended), black has the time to save his queen, rook and bishop

1. b4
Since this isn't a duplo action move, black has the time to save his pieces.


The main line:

1. Qd1

• action 1 and 2: duplo attack against B and R
• action 3: make the bishop B.A.D. (Barely Adequate Defended)

1. ... Rd6

• action 1: defend the rook
• action 2: lose a tempo

2. Rd4
action 1 and 2: reinforce the duplo attack

2. ... Bb3

• action 1: attacks the queen
• action 2: attacks the rook

3. Rg4+

• action 1: check
• action 2: save the rook

and white can cash in the bishop.