Seven spice chili mix. しちみとうがらし。七味唐辛子。
Lit. "Seven Flavor Chili." At least six different spices are added to togarashi (chili powder). The formula is flexible, depending on the region of Japan and the shop, but some elements usually added are: sansho (Japanese pepper), sesame, shiso, aonori.
A popular condiment for noodle dishes (the soups of udon and soba, so only the warm varieties of these noodles), nabemono (hotpot dishes) and yakitori.
[Shichimi togarashi. Photo Ad Blankestijn]
Famous types are the Yagenbori shichimi of Tokyo and the Kiyomizu shichimi of Kyoto. That last one is sold in the 350 year old Shichimiya Honpo located on the hill leading up to Kiyomizu Temple (at the corner of Matsubaradori and Sanneizaka).
Another interesting condiment shop is in Kyoto Hararyokaku (est. 1703) on the corner of Hanamikoji and Shijodori, so in Gion. This shops sells for example black shichimi in nice bamboo containers.
Japan Times article about shichimi.