just a few questions
what is a lai-to?
An iai-to is a sword made for practicing the art of Iai-do (drawing a sword and cut in one fluid motion). It is usually molded instead of forged and it willnot cut anything harder than pudding but it is far less expencive than a real japanese sword (shinken) and is a rather good substitute when practicing. On the 'HOME' section of Aikiweb theres a link in of the month in the bottom right corner to a MA-magazine and in one of the issues I found a very good article about the origin of Iai-do. Check it out.
Also check out http://www.tozando.com
they both have information on iai-to as opposed to the real japanese swords.
As far as Tan-ren goes - i can't help you right now.
anyways forgive my naivety