Kosh means «double». Ensemble includes 2 buildings: Modari-khan Madrasah and Abdullah-khan Madrasah. The buildings stand on narrow street sides, faced partal to each other. Modari-khan Madrasah was built in 974 of hydjr or 1566 - 1567. The date is pointed out with poems on majolica paintings over entrance. It is the modest model of Madrasah with gorgeous-faced main facade. He built abdull-khan Madrasah in 1558 – 1590.
It is one of outstanding Central Asiatic architectual work. Here architector bravely deviated from canon rules in planning, moving capacities assimetrically beyond the rectangular building outlines, including new forms in usual composition. So there was appeared inside yard spacious hall with cupola on twelve-sided light drum, it is known as «Abdullah-khan sky-light». The hall combines 20 hydjrs, situated in 2 tiers.