# Max percentage of mating pieces

In the newest SCHWALBE, positions are given where any piece on the board can give a check (any being surprisingly high). A quick dabbling seems to prove that it is not possible that any piece can mate. (Only try is something like Kf3 Qg2 - Kd5 Qc6, but how to take the flights?)

Thus the next best would be "Find a position where a maximal fraction of pieces can mate". (Of course we suppose either side may have the move.) What is your record attempt?

EDIT! "Can mate" is unprecise since in the case of a battery it is a priori unclear who mates (you can argue for both positions). I usually go for "only a piece that checks can mate", but in this special case (as you can already infer from the first paragraph) I prefer the other interpretation and formulate more precise "Find a position where a maximal fraction of pieces can make a move (or more) that delivers mate".

``````[FEN "8/8/8/8/1Q6/K7/7q/k7 w KQkq - 0 1"]
``````

Example: 50% of all pieces can mate

It's easy to get 16/17 = 94.1%

``````[FEN "4B3/4Q3/3QQQ2/1N2B2N/4k3/1Q5Q/3PKP2/2R1Q1R1 w - - 0 1"]
``````

On further thought that's not legal for lack of a previous Black move. This should be fixable, but meanwhile I see that 19/20 = 95% is possible:

``````[FEN "8/3Q1Q2/3Q2R1/1Q3N2/n3kBQ1/1B6/n2RKP2/1n2QQQN w - - 0 1"]
``````
• I had thought Hauke's edit meant no batteries are allowed as that means neither piece can be counted as quite making the mate? Far as I read it, though, batteries are still allowed and the definition still reads the same. Dec 24, 2023 at 8:55
• Batteries are allowed but note that in Noams first example, Qe1 can't mate by moving (which is easily fixed). Second one might be the theoretical maximum (the idea with the bN is utterly brill). Dec 24, 2023 at 9:25

26/28, 92.86%, maximum.

``````[FEN "5k2/Q1Q1RBNQ/1N1B1Q1Q/1QN2Q2/1qn2q2/1n1b1q1q/q1q1rbnq/5K2 w - - 0 1"]
``````
• I see I shot myself in the foot. On the last SCHWALBE meeting a member introduced his book "Who mates?", and here it applies to the bishops. You can argue that the Bf7 mates (it moves) and that the Bd6 mates (it checks), but not both! I will edit the question accordingly. Dec 23, 2023 at 9:51
• Whose book is who mates? Can you give some details please Jan 23 at 2:42
• @Laska Both sides mate, all is symmetrical. Jan 23 at 4:39
• We can argue whether the Bd6 mates even if we allow mate without moving: it is only checking in a check mate after 1.Re8# but this particular check is not necessary for the mate (remove Bd6 and it's still mate ; the Re8 is doing the important check). 1.Re5?, OTOH, is not mate because of 1...Nxd6. Jan 25 at 10:20