AusBonsai

Client at work has this Japanese maple when it has its leaves it's very nice but seeing as it's winter it's obviously a little bare.... If you look closely you can see the wire scarring

It needs a bit of work.

I would be cutting back real hard to the 1st branch and regrowing from there.
this will get rid of the wire scarring ( you do not have to look too close), and it will create some taper in the tree which it lacks now

Let grow mad for a season or 3 and then chop again.

Ken

Agree with ken.... You could also plant at a slightly different angle to achieve a new leader and first main branch, by keeping the two lowest branches...

It looks like a Dissectum, don't chop it below the graft or you will have a palmatum.

Cheers,
Mojo