I know what you're thinking: what did Meiji Japan call pocketwatches before they had pockets? Because you know that portable and flashy Euro-accessories saturated society before shirts had even gotten their shoes on (so to speak).

Answer: they called them sleevewatches: sodedokei 袖時計, tamotodokei 袂時計. Or, more commonly (bah!) kaichūdokei 懐中時計; kaichū refers to the area between kimono and breast, where watches and contraband can be stowed, and, by extension, a hypothetical space-of-portation (thus, a kaichūdentō is a "portable electric lamp," i.e. flashlight, even in the modern age where no-one has a literal kaichū any more).

Better yet, Tsuchida Mitsufumi 槌田満文's Meiji-Taishō no shingo/ryūkōgo 明治大正の新語・流行語 ("Neologisms and buzzwords of the Meiji-Taisho period") quotes Sakabe Kōjirō 坂部甲次郎's Tokei gogen shō 時計語源抄 ("Selections from the etymology of [the word] 'Clock'") on some period pickpocket (suri) words for pocketwatch: kinman, ginman, monaka, meaning "golden manjū," "silver manjū," and "monaka" respectively.

This was the golden age of watch-related pickpocket slang: before long, everyone would move on to wristwatches, which are much more difficult to steal.