I've just read "an improved safety solver for computer go" by Xiaozhen Niu and Martin Müller, describing their work on the program 'explorer.' Focusing entirely on the end game, it seeks to prove that safe groups are indeed safe. Building on the work of Benson (I _really_ must track down a copy of that paper), and develop new algorithms for complex regions using merging to join them together. Very interesting stuff. I think part of the reason I find it appealing is that it is proof based rather the heuristic.
Their methodology seems a little unusual, in that they are building what is essentially a theorem proving tool, but only trialling it on positive examples, which seems little unsafe. Maybe I missed something or they discuss it in a different paper.
They introduce their algorithms in pseudo-code, which is convenient.
This kind of approach seems very appealing to me, perhaps because such non-heuristic work seems more solid than other work I've read, a better base to build upon.
The Computer Go Group at Univresity of Alberta: http://www.cs.ualberta.ca/~games/go/