Shomyo is Buddhist chanting — the kind that would have been part of the daily soundscape for anyone living in Muromachi-era Japan. I've been trying, slowly, to build some of that scaffolding for myself.
In Sokun's old manuscripts, we can read that the yuri in ichikotsu should begin like the quiet of a thatched roof. I have no idea what rain sounds like on a thatched roof — but a Zen monk from the 19th century pulled me directly into the scene.
I wasn't particularly interested in Ōmori Sōkun. His name would pop in my lessons but I hardly paid attention. He eventually managed to reach me the way most important things do — by appearing again and again until I stopped ignoring him.
I've known about the Saikō-sui koan for a while now. It's engraved on Ōmori Sōkun's tombstone — along with a note saying it was upon hearing it that the master found his vocation.