This is what I use. It same from Simon Albrecht.
That's a standard symbol I know, but that really looks line Henle Verlag
to me.
Andrew
%========
\version "2.23.11"
% left hand/right hand indicators
% from Simon Albrecht
% Note that a single note must be in a chord.
hook =
#(let ((direction? (lambda (n) (= 1 (abs n))))
(hook-markup #{
\markup \path #0.175 #'((moveto 0 0)
(rlineto -0.85 0)
(rlineto 0 3))
#}))
(define-event-function (direction on-line) (direction? boolean?)
(let* ((self-al (if on-line 0.6 0.31))
(self-al (if (= direction 1) (- self-al) self-al)))
#{
\tweak self-alignment-Y $self-al
\tweak extra-spacing-width #'(-.5 . 0)
\finger \markup \scale #(cons 1 direction) #hook-markup
#})))
%{
\score {
{
<c''-\hook #DOWN ##f> <d''-\hook #UP ##t>
}
\layout {
\context {
\Voice
fingeringOrientations = #'(left)
}
}
}
%}
%========