Tsuba holes? asymmetrical? why?

[Walking Man]

I've always been a bit curious to find out what is the significance of the holes in guard of traditional style swords, and why are they not symmetrical?
Answers are greatly appreciated. Thanks.

 

[knife saber]

Those two holes are traditionally for the kogai and kogatana, which fit into slots in the saya. The holes are asymmetrical because the tools are asymmetrical. They exist so that the tools can be removed without drawing the sword. (the handle for the kogatana is refered to as the kozuka, and so the hole can be referred to as the kozuka ana, rather than a kogatana-ana /end useless trivia)

Some tsuba only have a hole for the kogatana.