So. I did a little research and looked at a lot of awesome creations. And in the end I thought Tsukaiyin's style would absollutely include a pocket watch: a delicate chain across his coat on occasion. Maybe he only brings it out for special occasions...
Anywho. This is a basic design for a watch that is made to tell time in multiple dimensions, as Tsukaiyin is a traveler. I'm still working on the magic theory, but have pushed myself a liiiiiiittle thin recently, so this one will arguably remain unfinishedd. I'd also thought it might be cute to give it a little object spirit, since he's likely kept this same watch for a millennia or two.