Japanese safety boots, n. — Green’s Dictionary of Slang

Japanese safety boots n.

also Chinese parachute boots, ...safety boots, Japanese parachute boots, ...riding boots

(Aus.) thongs, flip-flops.

1993		Aus. Word Map 🌐 Japanese safety boots. thongs [...] ‘Along with the “safety boots” expression, I have also heard the expression as Japanese (Chinese) parachute boots’ .
2015		J. Miller Essential Lingo Dict. 98: Japanese riding boots or Japanese safety boots A pair of thongs. Also called Chinese safety boots. These are ironic terms as they are often made in Asia from cheap rubber and/or plastic and are unsuitable as footwear for safety or riding.