[Retros] Twisted knights/ "Un camp intact"/ "There is no place like home"

[raosorio at fibertel.com.ar]

Hi Nicolas,

Mutual knight sibling is a very rich field, already quite explored but there are
surely chances to improve some aspects.

A proper article would be useful to clear up the state of art on the multiple tasks:

* number of thematic moves
* number of total moves
* captures - non-capture
* motivation (capture, check protection, promotion)
* complementary strategy (Cerianni-Frolkin, Pronkin, etc)
* complementary features (thematic side homebase, opposite side homebase, etc)

and their combinations.

On the other side, your concept "Un camp intact en fin de partie justificative" 
(all these articles should be available in the Retrocorner) is what Andrey and I
named THB (Total Homebase) in our article "There is no place like home" (R. Osorio
& A. Frolkin, Strategems oct 2007).

We defined there the concept THC (Total Homecircuit) as the situation where a side
shows all its 16 men on their "true" homesquares. The difference within THC and THB
is, 
* THB could show "impostors" (knight sibling), being then THB-non-THC
* THC could show a promoted piece on the respective pawn homesquare (THC-non-THB)

This type of positions allows very similar diagrams resulting from completely different
strategy. We used the following examples,

Unto Heinonen, 
The Problemist 09/1991        THB-non-THC
---------------------------------------------------
rnbqkbnr/pppppppp/2Q2R1B/8/2P1PP2/5N2/PP1N2PP/4KB1R
PG in  12.0 moves
---------------------------------------------------                                
1.c4 Nf6 2.Qa4 Ne4 3.Qc6 Nxd2 4.e4 Nb3 5.Bh6 Na6 6.Nd2 Nb4 7.Rc1 Nd5 8.Rc3 Nf6 9.Rf3 Ng8 
10.Rf6 Nc5 11.f4 Na6 12.Ngf3 Nb8. 
mutual sibling, 12 thematic moves.

Roberto Osorio     
Original                      THC-and-THB
--------------------------------------------------
rn4k1/pp2nppp/2p5/8/r1b5/q1b5/PPPPPPPP/RNBQKBNR
PG in 12.0 moves    C+                          
--------------------------------------------------
1.Nc3 c6 2.Nd5 Qa5 3.Nxe7 Qa3 4.Nd5 Bb4 5.Nf3 Ne7 6.Ne5 O-O 7.Nxd7 Rd8 8.Ne5 Be6 9.Nc3 Rd4 
10.Nb1 Bc3 11.Nf3 Ra4 12.Ng1 Bc4.  
Composed as an antithesis to Unto's since 12 thematic moves are done but by double knight 
switchback leaving no impostors on the board.

Roberto A. Osorio
Strategems Oct 2007 "Can mate be delivered by the side which has all of its 16 men on their homesquares?"
-----------------------------------------------
rnb2rqb/pppp4/6p1/7p/6n1/7k/PPPPPPNP/RNBQKBNR
PG in 15 moves    C+ 
-----------------------------------------------
1.Nb1-c3 Ph7-h5 2.Nc3-d5 Rh8-h6 3.Nd5xe7 Rh6-f6 4.Ne7-d5 Ng8-h6 5.Nd5-c3 Ke8-e7 6.Pg2-g4 Ke7-e6 
7.Pg4-g5 Ke6-f5 8.Pg5-g6 Kf5-g4 9.Pg6xf7   Pg7-g6 10.Ng1-f3 Bf8-g7 11.Pf7-f8=N Bg7-h8 12.Nf8-e6 
Qd8-g8 13.Ne6-f4 Rf6-f8 14.Nf4-g2 Kg4-h3 15.Nc3-b1 Nh6-g4 16.Nf3-g1#   

"Can mate be delivered by the side which has all of its 16 men on their homesquares?"
An opinion poll over 10 master-level chess players in the Argentine Chess Club produced 100% of 
wrong answers (“No”).Referring to the Osorio & Frolkin's article, “THERE’S NO PLACE LIKE HOME”
(Using homesquares in SPGs)this is a white THC non-THB position showing the THC# theme. This diagram results from a triple circuit from and to homesquare performed by pieces of the same type (one type trick).

Roberto Osorio & Jorge Lois
Stragems oct 2007           Black moving men?
-------------------------------------------------
rnbqkbnr/pppppppp/2R5/2Q5/3P2K1/5P2/1PPNB1PP/4BN2
PG in 16.0 moves      C+
-------------------------------------------------
1.Pf2-f3 Nb8-c6 2. Re1-f2 Nc6-d4 3.Rf2-g3 Nd4xe2 4.Rg3-g4 Ne2-g3 5.Ng1-e2 Ng3xh1 6.Ne2-g3 Ra8-b8 7.Bf1-e2 Rb8-a8 8.Qd1-g1 Ra8-b8 9.Ng3-f1 Nh1-g3 10.Qg1-c5 Ng3-e4 11.Pd2-d4 Ne4-c3 12.Bc1-d2 Nc3xa2 13.Bd2-e1 Na2-b4 14.Ra1-a6 Rb8-a8 15.Ra6-c6 Nb4-a6 16.Nb1-d2 Na6-b8   

there are many  examples of THB positions with one or both knights having moved and all the other pieces of the same side remaining stationary. This case is different and its intention is to motivate a rhetoric question: why should one move any piece other than a knight if the final diagram is THB?

I think that many opportunities for original compositions are  still pending in this field.

Best,
Roberto