Swapping knights

Question

On a $3\times3$ grid we have:

with $8$ moves needed to swap the red and blue knights.

What is the minimum numbers of moves to swap the knights on a $4\times4$ grid?

score 4 · Accepted Answer · edited Apr 13 '17 at 12:50

4

It will take:

20 moves to swap the knights

This can be done as follows:

All credit goes to @klm123 for demonstrating a good way to visualize this in a similar puzzle.

edited Apr 13 '17 at 12:50

Community

1

answered Mar 05 '16 at 04:57

Zerris

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You seem to be missing some connections - B2 to C4 and D3, and C3 to A2 and B1. This does actually put opposite-coloured squares in reach of B2 and C3. – Zandar Mar 05 '16 at 07:39
Right you are - no idea how I missed that. As a result, we can make the solution more efficient. – Zerris Mar 05 '16 at 08:05

Herb · Answer 2 · 2016-03-05T05:23:43.937

0

I believe it is, in chess terms,

20 half moves, or 10 move pairs.

In algebraic notation:

 1.  N3b2 N2c3
 2.  Na1  Nc1 
 3.  Nb3  Nbd3 
 4.  Ncb4 Nc2 
 5.  N1d2 Nd4 
 6.  Nb1  Nd2 
 7.  Na3  Ncb1 
 8.  Nbc4 Nac3 
 9.  Ndb2 Nc2 
 10. Na4  Nd1

edited Mar 05 '16 at 05:23

answered Mar 05 '16 at 05:17

Herb

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Swapping knights

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