What is the fastest theoretical way to get checkmate from the opening position?

competition/games/chess/fools.mate New

New entry, edited from material collected for the archive and not yet in a released version.

Problem

What is the fastest theoretical way to get checkmate from the opening
position?  It can be done in only 2 moves...how?

-- M. D. Warren <mdw@unixfe.cc.rl.ac.uk>

A second version: What is the least number of moves that you can make
from the initial start of a chess game to achieve a checkmate against
your opponent?  Your opponent is playing the Black pieces, he is a
novice and will not impede your moves.  List your move(s).  Extra
credit: the name of the first computer to win a chess game against a
Grandmaster?

-- indy <indy1cache@iquest.net>

[ Editor: the second version was laid out beside a diagram of the
starting position, omitted here. ]

Show solution

1. p-kb3, p-k4
2. p-kn4, q-r5 checkmate

-- Daniel Green <danielg@autodesk.com> (January 1995)

White:     QP to Q3                Black:     KBP to KB4
           KP to K3                           KNP to KN4
           Q to KR5 Checkmate

Fool's mate.

-- Ryan Younce <cheshire@catt.ncsu.edu> (February 1996)

[ Editor: in the first answer Black mates on Black's second move; in
the second, where White must give the mate, White mates on White's
third move.  No answer to the extra-credit question was found in the
collected postings. ]