Hakutsuru means "white crane fist", and is a kata practised in some
Goju Ryu schools, usually taught to a select few students after
learning the rest of the kata syllabus. It is a white crane form, and
it's true origins are unclear. It is definitely derivative of the
Chinese white crane styles, but some versions have a uniquely Okinawan
flavour. Gokenki taught these forms in Okinawa, and to others in their
travels to China, but is reputed to have taught a different version to
different people on any given day, and this has probably added to the
confusion and mysticism surrounding the form.
Hakutsuru is not a Goju Ryu kata. It was introduced from China by Bushi (Sōkon) Matsumura, the founder of Shuri-te. There are now many forms of Hakutsuru being practised. This is one of them. (Please excuse the music!)