Each story of the pagoda（宝塔） is basically a square box with no bottom, built around twelve outer pillars, or gawabashira. The pagoda as a whole is, in essence, five stacked boxes.

Since each story is smaller than the one beneath it, the placement of the gawabashira moves inward as one proceeds up the pagoda, meaning that horizontal beams are needed to support the gawabashira of each story above the first.

In fact, these pillars rest on horizontal bases, which in turn are supported by taruki --- slanting（倾斜的） beams that run from the inside of the structure diagonally downward to the outside, where they support the eaves.

The weight of the upper story, pushing down on the inner ends of the taruki, would cause the outer ends to rise if there were no counterweight. The heavy tiled roof of the eaves performs precisely this function. In short, the taruki functions as a lever arm, while the top of the gawabashira serves as the fulcrum（支点）.

The story above bears down on the inner end of the lever, and the overhanging roof balances this load at the outer end. or, to put it another way, the heavy eaves are in effect sustained by the story above.

When one reaches the uppermost level, of course, there is no story above to counterbalance the overhang.