How to hold down 10 and 11 position in Bunkafu notation in different strings

I am trying to create an accompaniment using music dictation and record the Shamisen part for a UTAU cover of a song that is played at a Bon Odori in my hometown, but I don’t know how to hold down the positions 10 and 11 in different strings.
(Bunkafu notation. for every note, there is a 1 no ito-position 10, 2 no ito-position 11, and so on.)

How do I hold down the positions that are close to each other in different strings?
Thank you very much for your help.

Hey there.

I might be misunderstanding your question, but it seems to me that all you need to do is use two fingers.

Or is there something stopping you from doing so?

My fingers are so thick that they almost get tangled.

I see, I see. You must have a very thin-necked instrument too!

I think the intention is to use two fingers (probably 人差し指 and 中指), but you might try stretching your finger over both strings. You could also get a kind of capo if all of the notes are in the higher octave.

What is the name of the song?

The Hosozao is not yet in perfect condition (under repairing), so it is a Chuzao short-necked Nagauta body minyo shamisen.

What is the name of the song?

Shin Kasahara Ondo.
ヤフオク! - [試聴]和モノ企業モノ自主盤 音頭 英亜里 // 新… (