An improved `record' was obtained by G.Ponzetto from Italy published in 'T&C-Scacco!' , January 2000.
1.e2-e4 d7-d5 2.e4xd5 Qd8xd5 3.Bf1-d3 Qd5xa2 4.Bd3xh7 Qa2xb1 5.Bh7xg8 Qb1xc2 6.Bg8xf7+ Ke8xf7 7.Ra1xa7 Qc2xc1 8.Ra7xb7 Rh8xh2 9.Rb7xb8 Rh2xg2 10.Qd1xc1 Rg2xg1+ 11.Rh1xg1 Ra8xb8 12.Qc1xc7 Rb8xb2 13.Qc7xc8 Rb2xd2 14.Qc8xf8+ Kf7xf8 15.Rg1xg7 Rd2xf2 16.Rg7xe7 Kf8xe7 17.Ke1xf2 diagr
I.e., the record went down from 17 to 16.5 moves. It probably will be very hard or impossible to bring this record further down.
The following is a short proof of the theoretical mininum:Who is able to solve this problem entirely? I.e., can you either improve the record further, or give the proof that 16.5 is indeed the absolute minimum?
There are 32 pieces on the board at the start. To reduce the number down to 2 kings requires 15 captures on each side. Also since there is no first move that allow either side to capture a piece of the opponent, so there is at least one non-capturing move. So the theoretical mininum is 16 move on each side.
The only move that deviate from the theoretical optimum is move 3.Bf1-d3 Qd5xa2. Perhaps this insight might help either in finding the theoretical best or proof that there is no way to beat 16.5.