[Retros] Add pieces
hwatheod at cs.stanford.edu
Sat Mar 12 01:32:19 EST 2011
On Sat, 12 Mar 2011, Noam Elkies wrote:
> Theodore Hwa <hwatheod at cs.stanford.edu> writes:
>>> it would be difficult to compose a problem in which it is not
>>> possible to add an additional piece (although not impossible).
>> Here's one possibility with 30 units, nobody in check:
>> Starting from the initial position, remove the queens,
>> and move the kings over to the queens' original squares.
>> It is not possible to add any pieces.
> Neat. Possibly reducible to 28: move each King one square further,
> removing the Bc1 and Bc8. Or even 26, going back to T.Hwa's position
> but putting a2,h2,a7,h7 on b3,g3,b6,g6 and removing all four Knights
> (or some suitable combination of Knights and Rooks). 26 could then
> also be attained by a mixture of the two techniques: put the Kings
> back on c1 and c8, and play only h2xg3 and h7xg6; or put just wK on c1
> and add a7xb6.
Extend this technique to achieve 22:
Remove all queens, knights, rooks. Move kings to d1/d8. Move a2,a7,h2,h7
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