Two reasons - Kanjincho is based on a much older Noh play (Ataka) which includes much beautiful poetry (see here and here) and I am learning to play musical excerpts for Kanjincho on my shamisen!
After many hours practicing my shamisen I became curious about the story behind the music, especially since I was already (trying to) learning the music behind the story! Here is the story behind the play's title "Kanjincho" as I understand it in my own words:
The Story of Kanjincho
Set in mid 12th century, a Noble (Togashi) is charged with guarding a barrier gate; he must prevent the great warrior Yoshitune from passing - Yoshitune is rumored to be traveling disguised as a simple porter.
Of course Yoshitune IS disguised as a porter and his traveling companion Benkei pretends to be a Buddhist priest traveling the countryside asking for donations.
When they approach the gate, Togashi is immediately suspicious - he asks for their Kanjincho, a scroll listing the names of those who have donated so far.
Benkei, clever one that he is, produces a blank scroll and pretends to read from it. Of course, Togashi isn't fooled by these antics, but is amused and lets these guys slide.
In the picture, Benkei is in front and Togashi is in back.
There is of course far more to the story, I have really only described why the play was titled "Kanjincho".
There is an Akira Kurosawa film loosely based on this play; it is titled "The Men who Tread on the Tiger's Tail" - very fun movie to see!
