Info wanted Blake Hitch ?

Hi Everyone,

Several years ago a tree surgeon showed me a knot he used while
climbing about the tree top. He called it a Blake Hitch. It was tied
in the bight of the line and around his body. It was also adjustable
and he could keep the slack out of the line that was tied to a limb
about as he moved up the tree.

I've forgot how to tie it and have lost my notes on the knot.

Anyone here ever heard of it or any thing similar?

Thanks,

Bertie