This page allows you to practice your technique for checkmating a bare King. Select the two pieces you want to play with through the buttons, and then press 'Calculate'. Then wait until the program has finished generating the endgame table. Then you can start playing: just move a piece of the side you want to play with, and the computer will reply with the best move of the other player.
This applet is exclusively for 3vs1 endgames. For practicing 2vs1 endgames, go here.
3 vs 1 checkmating
graphicsDir=bpainter/
whitePrefix=w
blackPrefix=b
graphicsType=png
squareSize=50
useMarkers=1
enableAI=0
symmetry=none
promoZone=0
maxPromote=0
Fairy piece:X:N:knight:a1
Fairy piece:Y:N:knight:b3
King::K:king:b2,,d4

piece 1:piece 2: 
Generating endgame table; Please wait. 

The statistics table indicates how many positions exist that are mate in N (with white to move) and mated in N (with black to move), where the number of full moves N is given in the third column. The bottom row gives the total of the columns as a percentage of all possible positions. In generally won endgames the first column would sum up to nearly 100%, in generally drawn endgames the second column would sum up to about 0%.