checkmate with 3 pieces

is it possible to checkmate with a bishop and a knight?

Only if the opponent blunders. I don't think it can be forced.

well it is possible

http://en.wikipedia.org/wiki/Bishop_and_knight_checkmate

2 knights is not - unless the opponent blunders

http://en.wikipedia.org/wiki/Two_knights_endgame

give me puzzle

It can be done.  I have Fritz 8 and it has lots of end game exercizes.  There are 2 examples of Knight and bishop.  The first is fairly straightforward, because the black king is already on the side of the board, with the knight and bishop in nice places.  The checkmate takes up to 22 moves (for me).  The secret is not to move your (white) king off the 6th row and when you do move it, you move it sideways towards the corner that you want to do the checkmate in (this will be the corner with the same colour as the square of your bishop).  You must keep restricting the squares that the enemy king can go to so, that when he is in zugzwang, he goes where you want.  Play waiting moves, by moving your bishop along one square, when necescarry.  The 2nd one is quite difficult, because even once you have forced the king to the side (or wrong corner) your bishop or knight may be in the wrong place.  The best is to use your knight to attack the corner square (opposite colour to your bishop's square) so that the enemy king can't get keep going back there.  But you must get to the start position of puzzle 1 to get things rolling.

I have spent a lot of time playing out all the moves, with comments, but I just can't get the thing to load onto this page.  I haven't even been able to save it.  The actual checkmate was a lot easier than posting a game on this site.

I will try to load the start position...(this is a test)

I will try again with the whoe move sequence:

KNB is always won for the attacker. here's a small tutorial I wrote a couple of years ago, with an example. maybe it'll help.

http://burncastleburn.blogspot.com/2006/12/mating-with-knb-vs-k.html

I'm going off of my memory at the moment from my Silman's Endgame book, so I may have forgotten something, but I believe the following is correct.

You can force wins with the following:
KQ v K
KR v K
KBB v K
KBN v K

You can't force wins with the following:
KB v K
KN v K
KNN v K (you can win this only if your opponent willingly walks his king into a corner)

These types of questions are critical and must be memorized in order to direct games into draws if you're down, or into victories if you're up.

This is the 2nd (more difficult) knight/bishop checkmate puzzle provided by Fritz 8.  As I see it, in this case there is no move sequence to remember, because black has to many options. This is how I played it a few minutes ago: