Make one knight from each kingdom into a ruler for the others.
It's quite simple for a knight to become a king - one touch is all it takes.
One more touch, and he'll turn back into a knight again.
Each kingdom must have exactly one king.
There must also not be more than two kings or two knights in a row, horizontally, vertically or diagonally, unless separated by one or more empty spaces.
Once you've appointed your kings, touch the 'Submit' button.
Any kingdoms in breach of terms will be coloured an embarrassing red.
But you'll have a chance to put things right, don't worry.
Answer for 'Neighbouring Kings 21'
The answer is as follows.