You can comment as the game is over (I guess).

I thought I'd figured out the rules, but now I'm sure I must have gotten something wrong.

In this position, it looks to me as though my opponent has created a stack of 5 with no blue.

Shouldn't I have been able to claim blue and capture his stack a blue piece, winning the game?

What rule caused the game to be over in his favor just before that?

He obviously played that move intentionally, so I assume that he saw a reason for it to be a win for him.

It is not linked to lyngk move (using a network of claimed colours).

The move that makes the win is due to the use of jokers, as I posted in original thread, jokers can be stacked up, so in this tower of six, one of the jokers is indeed a blue piece giving Zugzwang the win.

Ah, I see.  There were 6.  I had to zoom in many times to see that there were two jokers in that pile.

Thanks, Caroll.