The Sparing Troll
There was a discussion in the ThudBoard forum about a very fine point of the rules: a troll can spare any or all of the dwarfs it lands by.
I had a confirmation from Trevor today:
It's in the rules - capturing is not compulsory (see under the heading CAPTURE). Therefore taking some dwarfs but not all is perfectly legit.
[....O]f course, any dwarf left uncaptured next to a troll can capture the troll on the dwarfs next move - so why leave it when it can be taken along with the others?
This question was answered by a mystery player (whom we've dubbed "the Masked Thudplayer"), anonymously posting a layout that demonstrated a situation where a troll sparing a dwarf would be The Right Thing To do (and not just because that troll, him diamond).
One great charm of the Masked Thudplayer's layout is that it's feasible: the trolls have moved at least 17 squares. There are 14 displaced dwarfs, each of which can be returned to a unique edge square in one move, and two missing dwarfs by the troll in the top right, at least one of whom must have moved. So both sides have moved about the same amount.
I believe this ability for it to be played was either a deliberate point of the layout, or a product of how the Masked Thudplayer developed the layout.
So not only do we have a layout the demonstrates a situation where a troll might wish to spare a dwarf, but it's possible to recreate a minimal (though as pointed out in the original post, improbable) game that could produce this layout.
Here's one game. The order I have the moves is fairly arbitrary, though many of them must be made in sequence, moving into position before they're blocked. I admit I've not verified this works in any way, though: ThudBoard itself might laugh at me for it
dE2-E10 TG9-D9xE10 dF1-F2 TD9-C9 dN4-K4 TH9-G9 dM3-M4 TG9-F10 dO8-O5 TF10-E11 dF15-O7 TG8-F8 dP7-P8 TF8-E7 dC12-H12 TE7-D8 dD13-H13 TD8-C7 dB5-J12 TG7-F6 dK15-K11 TF6-E6 dL14-K13 TJ7-H6 dG15-K12 TH6-G5 dJ15-J13 TG5-F4 dM11-M14 TF4-F3xF2 dN11-N13
Since the limiting factor is the number of dwarfs displaced, I believe it may be possible to get the game ONE move (troll + dwarf) shorter, by not moving the dwarf from E2 (and just taking it in situ instead). Since that would only allow the trolls 14 moves to travel 17 spaces, it will require some VERY cunning shoving, if it is even possible.
So: try to produce the layout below, in 14 troll moves and 15 dwarf moves!
I'll try (no promises, though!) to find some prize of sorts for anyone who manages it, or who manages to prove that it's conclusively not possible.
a b c d e f g h j k l m n o p 1 . d . d d 1 2 . . . . . . d 2 3 d . T . . . . . . 3 4 d . . . . . . d . d . 4 5 . . . . . . . . . . . . . 5 6 d . . . T . . . . . . . . . d 6 7 d . T . . . . T . . . . . d . 7 8 . . . . . . . X T . . . . d d 8 9 d . T . . . . . T . . . . . d 9 10 d . . . . . . . . . . . . . d 10 11 d . . T . . . . d . d d d 11 12 . . . . . d d d . . . 12 13 . . . . d d d . . 13 14 d . . . . . . 14 15 . . . . . 15 a b c d e f g h j k l m n o p