[TUHS] Unix v6 chess source code?

Hello! I saw someone playing chess on their pdp-11 and thought it could be an interesting project to run on my pdp-11. At this point the RK05s are not yet running so booting unix v6 is not possible. I then thought that if the source code could be found it might be possible to get it to run standalone with some modifications. After some googling I found the archive https://www.tuhs.org/Archive/Distributions/UNSW/7/record0.tar.gz which contained a chess.lib file. It appeared that this archive contained source code for some kind of chess program. I have been told that it isn't the chess written by Ken Thompson so the question is who wrote it? There are not many comments in the code. Could be interesting to know more about this chess implementation. Just looking through the source files and the mk file show that it is missing a set of files. The mk file references a set of "b"-prefixed assembly files, bgen.s, bmove.s, bheur.s and bplay.s which are present in the archive. But it also references a set of files with "w"-prefix, wgen.s, wmove.s, wheur.s and wplay.s which are missing. I also recognise that there is an include file, "old.h" that is included from all c-modules that most likely is present in the overload.lib which seems to be an overlay loader. Anyone that has an idea how this thing was built once upon a time? /Mattis