Chika Bhaban lies within the gaur citadel to its south-east corner and is in alignment with the gumti gate to its east. The building is so named because of the bats that swarmed inside it prior to its repairs. It is square in plan, and was built on the same principle as the eklakhi mausoleum at Pandua. Hence early explorers, including Alexander cunningham, who made a thorough survey of the area (Archaeological Survey Report, XV, Calcutta, 1882), thought it to have been the tomb of Sultan Nasiruddin Mahmud Shah (1435-36'1459-60 AD), the founder of the dynasty that came to occupy power after the House of Ganesha interregnum, to which the Eklakhi Mausoleum belonged. A corridor, which ran at the front of the building, however, negates this view and corroborates the traditional belief that it was built as a daftar khana (an office building).
The austerity of the building is in contrast to the Eklakhi Mausoleum, and together with ruins of other structures on its sides strengthens the latter contention. The existence of long rows of pillar bases to the west of the building suggests a stable. The Chika building, part of the administrative office of the sultan and built in alignment with the Gumti Gate of the citadel of Gaur, could very well have been built by the ruler who built the citadel and the gateway, ie Nasiruddin Mahmud Shah.
The Chika building measures 12.80 sq.m inside. It has an outside dimension of 21.65 sq.m, the thickness of the wall being 4.52 m; it is the thickest building in Gaur-Lakhnauti. The hemispherical dome rests on squinches. Outside walls of the building are patterned with vertical inset and offset panels, divided by a string moulding, which runs around the entire building, including the round towers at the corners. The cornice is carved and was once decorated with tile works, traces of which could be discovered at the time of Abid Ali Khan. Inside the building and within the spandrels of arches are still visible the remains of tile work in the form of medallions. [ABM Husain]