Mokoshi

In Japanese architecture a mokoshi (裳階・裳層, also pronounced shōkai^?), literally "skirt storey" or "cuff storey", is a decorative pent roof surrounding a building below the true roof. Since it does not correspond to any internal division, the mokoshi gives the impression of there being more floors than there really are. It is usually a ken deep and is most commonly seen in Buddhist temples and pagodas (see for example the article tahōtō). The mokoshi normally covers a hisashi, a walled aisle surrounding a building on one or more sides, but can be attached directly to the core of the structure (the moya), in which case there is no hisashi. The roofing material for the mokoshi can be the same or different (see for example's Hōryū-ji's kon-dō) as in the main roof.

The name derives from the fact that it surrounds and hides the main building like the cuff (裳裾, mosuso^?) of a pair of pants. Its purpose was in fact to hide the thick sustaining pillars of the structure, making it look lighter and simpler. It has been used extensively by the Zen sects in various structures of its temple complexes.

Another name for a mokoshi is yuta (雪打, lit. snow strike^?), hence the name yuta-zukuri (雪打造, yuta style^?) given to the style of a building featuring it. This name started being used during the Middle Ages, and stems from the idea that its presence offered protection from snow.

...
Wikipedia