Tatami (ç³堷足), or tatami gusoku (from ç³ã tatamu, "to fold", and gusoku, "full suit of armour"), was a type of lightweight portable folding Japanese armour worn during the feudal era of Japan by the samurai class and their foot soldiers (ashigaru). The Tatami dà  (a foldable cuirass) or the tatami katabira (an armoured jacket) were the main components of a full suit of tatami armour.
A ' (complete suit of folding armor) includes a tatami dà  or ' (jacket) and a tatami kabuto (helmet) ', or ' (hood) or similar type of head protection along with the other related parts of a full suit of Japanese armour. Collapsible head protection such as ' and other collapsible armor are also tatami armor; a traditional kabuto could also be part of a tatami gusoku.
Tatami armour was lightweight, portable, convenient for transportation, and they were manufactured inexpensively for the ashigaru light infantry. Tatami armours were worn by all samurai classes from the highest class to the lowest class. The higher class samurai wore elaborate armour while the lower class samurai and retainers wore simpler versions.
In his book Arms and Armor of the Samurai: The History of Weaponry in Ancient Japan Ian Bottomley shows a karuta tatami do and a karuta tatami kabuto (p. 88), and discusses different types of tatami dà  karuta gane dà  and kikko gane dà  on p. 91. George Cameron Stone shows a kikko tatami armor on p. 606 of his book A glossary of the construction, decoration, and use of arms and armor.