Although Tatami in the Japanese culture is a word that designates floor covering, for us shoe addicts is designates a shoe line part of the Birkenstock family. The most famous one, to be precise. 
Sacai Luck, a Japanese label (!) part of Sacai brand, associated with the German footwear giant and together imagined a one again hit sandal. 
The signature Birkenstock designs is of course there but a Japanese feel (again) was added to it.
Right now, the sandals are available to shop at Colette.