After many years of mountaineering, bicycling, and adventuring, one of the most stead-fast rules I have found is "Believe Your Compass".
Only twice did the compass fail me:
Once when standing under an enormous power line.
Once inside of a car which, for some reason caused the compass to line up with the drive train.
Besides that, no matter how wrong you think your compass is, it is usually/always right.
EXCEPT... A couple of weeks ago I was touring around Japan and bought a Japanese made compass in order to get around. It appeared to me that the dark colored part of the needle was pointing south rather than north. I was dumbfounded. I used to live in Tokyo for several years and could not imagine that I had been so disoriented for so long.
Come to find out, in Japan, the dark colored needle points NORTH - completely opposite most of the rest of the world. Attached is a scan of that crazy compass for your entertainment.
That is the funny thing about Japan. They do things different just to be different sometimes. Maybe they do it to confuse the foreigners - but I bet it confuses the natives as well. For example, even though, as a rule, maps are supposed to be printed with the top being north, many of the Japanese map books digress from this rule when printing suits it better with north in a different direction (oops, did we forget to print compass north on the map?...)
Once, my Japanese friend and I looked curiously at a Japanese sign trying to figure out what in the heck it could possibly be saying. We then realized that it was a sign from the Taisho period (just the turn of the 1900's) and was written "sdrawkcab" (backwards). For some crazy reason, the Japanese decided to write horizontally from right to left for a short period of Japanese history, until they gave it up due to all the confusion it was causing.
In Japan, a lot of things are "different" - even compasses, so be careful if you ever plan a trip to or buy equipment in bizarro world. ...and let's hope Santa doesn't use a Japanese compass to get home this year or we might not be seeing him next year.