1) Yannick Kilian Chavanne, aka Yak, was the leader of the band Glowing Shade from Geneva (Switzerland). He recorded on his own an album titled 'In a Dim Ringing', in 2002, which sounds quite like experimental and minimalist alternative rock. He never performed it on stage.
2) YAK is an experimental hardcore band from Italy
3) The progressive rock band YAK from the UK were formed in 1982.
Proggers YAK have released 4 albums to date, the most successful being "Journey of the Yak" released in Nov 2008 - Steve Hackett recently described the album as "beautiful music".
All 4 YAK CD's are sold to raise funds for Tower Hill Stables Animal Sanctuary which is in Essex - see www.towerhillstables.com
The music of YAK is instrumental and reviewers often cite Camel & Genesis as reference points
4) A London-based trio composed of members Oliver Burslem, Andy Jones, and Elliot Rawson.