Cockney rhyming slang when refering to a mate, as in plate, china plate, mate... get it?

Used more back in the day by East London gangsters (and Del Boy in sitcom Only Fools and Horses).
East London Gangster: "How ya doin' me old china?"

East London Idiot: "Hey?"
by Jack-up man! August 30, 2005
"My (old) friend"
Your mate, you brother, your closest friend.
Country of origin: Wales (cockney)
China plate, plate rhymes with mate
Rob: 'ello petal, did you meet me old china at the pub earlier?
Liz: oh Wilfred? I thought you WEREN'T friends...
by lbdub February 9, 2022