Tilbage til Skak




# This file contains positions where INSUFFICIENT MATERIAL is the theme.

Fx. a lone bishop, a lone knight or even two knights cannot mate the enemy king.


# Dabbaba solves all of these positions.


#Not all the positions have a single move as the right( wrong) solution,

#because this test is also used to reveal when a program claims mate, draw or

#don't claim anything.


#Be aware that some positions may be solved by a program without the right

#knowledge, if it calculates deep enough and fx detects that a pawn is


#Such positions should be considered 'not solved'.

#Most positions should be solved 'immediately'. Only a few positions are allowed

#a longer search (they are in INSULONG.EPD). This is described below.


A lone bishop or a lone knight

KB1k4/8/8/8/8/8/8/8 w claim draw!

KN1k4/8/8/8/8/8/8/8 b claim draw!




kbN5/8/K7/8/8/8/8/8 w Nc8-b6+! both have insuff. material, but claim mate!



KNb5/8/1k6/8/8/8/8/8 b Bc8-b7+! both have insuff. material, but claim mate!



#These positions are almost as those above...

kb1N4/8/K7/8/8/8/8/8 w both have insufficient material; (claim?) draw!





KN1b4/8/1k6/8/8/8/8/8 b both have insufficient material; (claim?) draw!

Two knights

#If a program does not know that two knights cannot mate, it will capture the

#knight on b6, as this move wins both knights which are more worth than a


8/rKn5/1n6/8/8/k7/8/8 w Kb7xa7!




#Here comes the same position twice; with both black and white to move.

#Black should capture the white pawn on h2; white should save it.

#There are some rare positions, where you can win with two knights if the

#opponent has a pawn, so a stalemate can be avoided.

#But I doubt this is the case here, so concentrate on the white pawn on h2

#instead of the temtating knight on h1.

8/7N/7p/7p/7K/8/6kP/7N b Kg2xh2! best chance for a draw...


8/7N/7p/7p/7K/8/6kP/7N w h2-h3! gives an easy win

More about a lone bishop or a lone knight

#Many programs will not capture on a8, which is a sure draw.

#They play -,Kc6 and feel an advantage of more centralised pieces!
And the bishop is more worth than a knight!

N6K/1k6/8/8/4b3/8/8/8 b Kb7xa8!





#Here the positions show, if your program will sacrifice a piece to get a


#It is likely, that the program will not show a draw score, as black will not

#capture the piece, but prefer a more centralised position as above.

1B5K/1n6/1p6/2k5/8/8/8/8 w Bb8-a7!



7K/Bn6/1pk5/8/8/8/8/8 w Ba7xb6!



#The same as above, but leaving black with a lone bishop instead of a knight.

#This is a little more tricky, as Nc8-b6+ in a short search seems to win the

#black bishop, but a little longer search shows that black with Kc5-c6-b7 wins

#the white knight.

#The position ought to be solved 'immediately' (3-ply search; no extensions).

b1N4K/8/8/1p6/2k5/8/8/8 w Nc8-d6+!




b6K/8/3N4/1pk5/8/8/8/8 w Nd6xb5!




#Here will Nd8-e6+ win the bishop without the knight gets caught, but a longer

#search (not allowed in this test) will show, that black promotes his pawn.

1b1N3K/8/8/8/3k1p2/8/8/8 w Nd8-e6+!






#Here again some positions with the lone knight bishop as the theme.

#The positions are duplicated with without a black pawn on f5.

#Some programs may only recognise insufficient material when one of the

#parts have a lone king and is fooled by the black pawn on f5.

#The pawn on f5 may also delay a deep search (not allowed!) to understand

#that the white pawn gets promoted.

8/8/8/5p2/5K2/8/3NkP2/8 b Ke2xf2!



8/8/8/8/5K2/8/3NkP2/8 b Ke2xf2!



8/8/8/5p2/5K2/8/3BkP2/8 b Ke2xf2!




8/8/8/8/5K2/8/3BkP2/8 b Ke2xf2!





#A special case with the same material as above. A long search will show, that

#it is correct to capture the knight here, as black promotes first and wins.

#So this is only a test of insufficient material rules, that they do

#consider the result of a long search.

#At least 11 ply should be searched in this position.

8/p7/8/8/7K/8/5NkP/8 b Kg2xf2!



More about Two knights

#Now two positions each with 3 moves, where 2 knights is the theme.

8/8/8/8/3N3B/2N5/3k2K1/4r3 w Bh4xe1+! Gives an easy win.



8/8/8/8/3N4/2N5/3k2K1/4B3 b Kd2xe1? Don't play this and claim draw.



8/8/8/8/3N4/2N5/6K1/4k3 w Nd4-f3+! Don't claim draw, but mate.




#Here both parts have insufficient material, but white wins with a quiet move.

8/8/8/6N1/6b1/8/5K2/5N1k w Ng5-e4! Don't claim draw, but mate.





8/8/8/8/4N1b1/8/5K2/5N1k b Don't claim draw, but mate.



8/8/8/8/4N3/5b2/5K2/5N1k w Ne4-g3+! Don't claim draw, but mate.



Pawn(a/h) and the wrong bishop

#Now the theme is pawns on the a-file or h-file combined with a bishop on the

#wrong square-colour.

#Don't capture the bishop in this position although it is more centralised

#than the knight and it is more worth than the knight.

#This may take a little search to solve, if the program is constructed like

#Dabbaba, that only recognises the position as draw when the black king is on

#the four squares nearest the corner.

#A search to a depth of 11 ply is allowed here, so the king can reach h8.

#But a very, very deep search showing the knight can help the pawn to

#promote is not allowed.

8/8/2NkB3/8/8/8/7P/7K b Kd6xc6!






#Black must keep control of the corner and not 'escape out in the free' with

#-,Kf8 as white wins with Bg6-h7.

6k1/8/6BP/8/8/8/7K/8 b Kg8-h8!





6k1/8/6BP/8/8/7P/7K/8 b Kg8-h8! An extra pawn on h3 may confuse some programs






#After -,Kxh6? Kg8,Kg5 (-,Kg6 h4,Kh6 h5,Kg5 Kg7) Kg7,Kh4 Kh6,Kg3 Kg5 white wins

8/5K1k/7P/8/6B1/7P/8/8 b Kh7-h8!




#Here comes a position in 4 versions:

#With without pawn h2 and with without bishop e8.

#Fx will Genius2 only play -,Bh3! if there is a pawn on h2 and no bishop on

#e8! Genius5 manages it if there is no bishop on e8 (h2 does not matter)

B1b4k/8/8/8/8/8/6P1/5K2 b Bc8-h3!






B1b1B2k/8/8/8/8/8/6P1/5K2 b Bc8-h3!





B1b4k/8/8/8/8/8/6PP/5K2 b Bc8-h3!





B1b1B2k/8/8/8/8/8/6PP/5K2 b Bc8-h3!




Two bishops on the same square-colour

#In the above positions, a new theme was introduced:

#Two bishops on the same square-colour. They cannot mate a lone king.


#Fx Genius5 does not know immediately, that it should capture on b8. For 2

#minutes it considers -,Kxc6?? on a 50 Mhz 486.

1BB5/2k5/K1B5/8/8/8/8/8 b Kc7xb8!





#This example is taken from PLY 1996/2 page 16 and is the only example that I

#know from practical play.

#White cannot move his bishop: fx Bd5,Bc6 Bf7?,Bc6 e8Q,Bxg2+ mate.

#Promotion to anything else than a knight is answered by -,Bxg2+!

#Genius5 finds the right move here.

8/4P3/2B5/8/8/6p1/5kP1/5b1K w e7-e8N!




Problems solved by a longer search

# unsufficient materiel - these take long time to solve

# and they are allowed long time (11 ply) to solve

8/p7/8/8/7K/8/5NkP/8 b Kg2xf2!



8/8/2NkB3/8/8/8/7P/7K b Kd6xc6!