The grab theme

Here is one of the first three move themes on the blog.  The grab theme goes back to the time of Loyd.  The idea is that Black has a free piece that it can move instead of dropping it guard.  White's strategy is then to capture this piece wherever it goes.

Moen, Kabe
The Problemist Supplement 2015

#3

6 + 4

Moves by the bQ or bP lead to immediate mate.  Moreover, moves by the bS lead to immediate capture which will then force the bQ or bP to relinquish their position.  We have a complete block.  White only has to try to preserve the block.  1.Kd6? attempts to do this but 1...Sc6 foils the plan because 2.Bxc6 is met by the check 2...Qxc6+.  The only move that works is 1.Ba8! which holds the block but also introduces some new play by exposing the wK to checks.  This is probably one of my best keyed problems.  

Kipping, Cyril Henry Stanley
The Chess Amateur 1911

#3

11 + 3

Here is a bQ from the grab master C.S. Kipping.  Notice that the bQ can be captured in the initial position but Black has 1...Sb7 to answer this.  Instead 1.Bc8! solves and the bQ has 27 moves that all lead to capture.  

Loyd, Samuel
Newark Sunday Call 1877

#3

5 + 2

Loyd uses the grab theme in conjunction with the indian theme.  The idea is that capturing the bB will induce a stalemate, so the key 1.Rh7 clears the way for the pawn to relieve the stalemate 1...Be7 2.fxe7 Kxa7 3.e8=Q.
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Hannemann, Knud Harald
Aftonbladet 1925

#3

10 + 4

Here is an amazing double bS grab with a good flight giving key.  1.Rb8 leads to 16 different captures of the bSs.   

Warton, Joseph and Warton, Thomas
The Observer 1949

#3

9 + 5

We end with a Warton brothers classic.  Since it is a Warton problem we expect some type of mutate and indeed all moves by Black have set continuations: 1...R ~ 2.Bxb7 1...b4 2.Bc4 1...B ~ will be grab unless 1...Ba2 2.Sc2 ~  3.Sb4.  Waiting moves by the wR are countered by an appropriate move of the bB so that 2...Rd8 pins the wB.   What remains is 1.Rh7 so that the rook on the fifth rank can grab the bB on g6 or h7.  The tries 1.Bf3,Bg2 fall to obstruction 1...Bd3!