pachinko nail adjuster
Colloquial term for a pachinko parlor employee who adjusts the machines' nails to control payout rates and profitability.
He has worked for many years as a nail adjuster at a pachinko parlor.
Compound of 釘 (kugi, 'nail') and 師 (shi, 'master' or 'specialist'), referring to a person who adjusts the nails in pachinko machines.