US Imperial and Metric aren't the only two measurement systems in the world jfc
rice cooker plastic cups are "about 4/5 of a US cup (but 2/3 is close enough and a common measure)" and "about 180ml" and "3/4 of a metric cup.
why? because they're 1 gō, the standard rice measure for two people in Japan (and the ge for China)
or, about a wooden sake cup.
at least be informed about your pedantry or it leaks into imperialism??? c'mon folks. Not everything is made for you and you can look up the conversions easy.
