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# Chess problems: A proof game

A nice form of `retrograde' chess problem is the proof game (also often called: shortest proof game.)

In this problem, we are given a position, and the task is to find the moves of a chess game that realizes the position in exactly the given number of moves.

The following problem, composed by Tibor Orban, and first published in Die Schwalbe, 1976 received a `commendation'. It looks simpler than it is. The position is actually quite easy to realize in 3.5 moves, i.e., after the fourth move of white, but the task is: This is the position after the 4th move of black. How did the game go?

There is a unique solution.

FEN: rnbqknbr/pp3ppp/2p1p3/8/4P3/8/PPPP1PPP/RNBQK1NR.

## Solution

Congratulations to Alfred Pfeiffer, who was the first to send in the solution to this problem.
Written by Hans Bodlaender.
WWW page created: May 6, 1998. Last modified: May 25, 1998. ﻿