[Retros] rstan

[Francois Labelle]

Every problem is sound according to my computer. Here are the solutions, 
each with 2.0 moves added to the shortest line.

NDE2004:
1. e4 h5 2. Qxh5 g6 3. Qxg6 Nf6 4. Qxf6 e5 5. Qxe5+ Be7 6. Qxh8+ Bf8 7. 
Qe5+ Be7 8. Qh8+ Bf8 9. Qe5+ Qe7 10. d3 d5 11. Kd2 Bg4 12. Kc3 Bh5 13. 
Qxh5 Qb4#

Andrew1:
1. e3 f5 2. Qh5+ g6 3. Qxf5 e6 4. Qxe6+ Qe7 5. Qxg6+ Qf7 6. Qe6+ Qe7 7. 
Qg6+ Qf7 8. Qe6+ Qxe6 9. Ke2 b5 10. Kd3 Qc4#

NDE:
1. e3 f6 2. Bd3 Kf7 3. Bg6+ Ke6 4. Bf5+ Kf7 5. Bg6+ Ke6 6. Bf5+ Ke5 7. 
Bxd7 e6 8. Bxe6 Qxd2+ 9. Kf1 Qxd1#

Andrew2:
1. e3 d6 2. Ke2 Bg4+ 3. Kd3 Bf5+ 4. Ke2 Bg4+ 5. Kd3 Bf5+ 6. Ke2 Bg4+ 7. 
Ke1 Qd7 8. Qxg4 Qb5 9. Qc8#

Andrew3:
1. d3 e6 2. Qd2 Ke7 3. Qg5+ Kd6 4. Qe5+ Ke7 5. Qg5+ Kd6 6. Qe5+ Kc6 7. 
Bd2 Qg5 8. Bc3 Qc1#

     François

On 10/01/2013 01:15 PM, Andrew Buchanan wrote:

> Minor error: the shortest line is 6.5 moves, because Bf5+ is required to

> eliminate the cook 1.e4.

>

> It's still faster the previous record, but faster still would be the

> following version:

>

> 1. d3 ... 2. Qd2 ... 3. Qg5+ ... 4. Qe5+ ...

> ...

> 4n+5. Bd2 ... 4n+6. Bc3 ...#

> (for n>=0)

>

> This will give a shortest line in 6.0 moves, and incidentally is

> capture-free.

>

> Thanks,

> Andrew.

>

> -----Original Message-----

> From: Andrew Buchanan [mailto:andrew at anselan.com]

> Sent: 02 October 2013 00:27

> To: 'The Retrograde Analysis Mailing List'

> Subject: RE: [Retros] rstan

>

> Or:

> 1. ... d6 2. ... Bg4+ 3. ... Bf5+ 4. ... Bg4+ then 1004. ... Bg4+ 1005. ...

> Qd7 1006. ... Qb5 1007. #

>

> The shortest line is just 4.5 moves.

>

> I don't think the term "half proof game" is right. Maybe "half synthetic

> game"?

>

> Cheers,

> Andrew.

>

> -----Original Message-----

> From: retros-bounces at janko.at [mailto:retros-bounces at janko.at] On Behalf Of

> Noam Elkies

> Sent: 01 October 2013 13:02

> To: retros at janko.at

> Subject: Re: [Retros] rstan

>

> "Andrew Buchanan" <andrew at anselan.com> writes:

>

>> What fun!

>>

>> The question arises. What is the shortest infinite game? :)

> (-:

>

>> Here is a quick effort.

>>

>> 1.e3 ... 2.Qh5+ ... 3.Qxf5 ... 4.Qxe6+ ... 5.Qxg6+ ... 6.Qe6+ ... 7.Qg6+

> ...

>> and eventually something like

>> 1008.Qe6+ ... 1009.Ke2 ... 1010.Kd3 ...#

>>

>> Is it sound? Can it be improved?

> An attempted improvement:

>

> 1 e3 ... 2 Bd3 ... 3 Bg6+ ... 4 Bf5+ ... 5 Bg6+ ... 6 Bf5+ ...

> ...

> 1007 Bxd7 ... 1008 Bxe6 ... 1009 Kf1 ...#

>

> (the repetition actually starts at move 3, not 5)

>

> NDE

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