Marshall's tricky variation: Black sacrifices a Pawn (and in some cases two Pawns) in order to get ingenious attacking chancesPetroff pg. 102N-B3 is correct.  The text allows a neat reply.

Towards the end of January 2005, I re-started up an interest in chess that had begun while I was working at Centre Accroche. Key to that was finding an opponent who played a good game and had some time to pay attention to the game during a two week long bout of e-mail chess.

Our next match is scheduled for Superbowl Sunday, celebrated together on the big screen with many church friends. We decided that for a few of us who aren't so into NFL football we'd have a chess tournament, same time same place.

position above:
1.P-K4...PK4
2.N-KB3...N-KB3
3.NxP...P-Q3
4.N-KB3...NxP
5.P-Q4...P-Q4
6.B-Q3...B-Q3
7.O-O...B-KN5
8.P-B4...O-O!?
9.PxP...P-KB4
10.R-K1?..........
see diagram above
10...........BxPch!
11.KxB...NxP
12.Q-K2...NxB
13.QxN*...BxN°
14.QxB...Q-R5ch
15.Q-R3...QxR

Chess links:

Picklyk - Dettweiler game, finished up around Groundhog Day.

Some useful, free chess software that I found on-line includes:

ChessPad, a PNG reader that allowed me to generate the cool
little diagrams in html format as seen top left on this page. Play
a game on this software and it will record the moves in PNG format.
*Now the Queen, one of the guards of White's King Rook, has been lured away
°And now the other guard has been removed