How do you say "using X as a Y"?


In Issunboushi, there is a line that goes like this. "Issunboushi wa hari wo
katana ni shite koshi ni sashi" I found a translation that says "He made use
of a needle as a sword", but I have no idea why. True, hari=needle,
katana=sword, but I couldn't find any grammar to help me understand the form
of this phrase. Where does the "made use" come from? What does "koshi ni
sashi" mean? Thank you in advance! :)




The part, "katana ni shite", means to use as a katana. *

As for the other question, "koshi ni sashi" is an old way of saying, to "put
in/on his belt". Koshi meaning hip, and sasu being the verb for insert/put in
[belt].

*Note that this is not the same as "ni shitemo", which is a pattern meaning "even if". 




The part, "katana ni shite", means to use as a katana. *

As for the other question, "koshi ni sashi" is an old way of saying, to "put
in/on his belt". Koshi meaning hip, and sasu being the verb for insert/put in
[belt].

*Note that this is not the same as "ni shitemo", which is a pattern meaning "even if". 

