The ōtsuzumi (大鼓), also called the ōkawa (大皮), is a Japanese drum shaped like an hourglass. It is a larger version of the tsuzumi or kotsuzumi and is used in traditional Japanese theater and folk music. It looks slightly different from the tsuzumi, and its sound is very different from the four sounds the kotsuzumi makes. The kotsuzumi is smaller and has a more decorated drum head, while the ōkawa is larger, with a plain, leathery drum head. The ōkawa’s sound is higher and sharper, like a dry, almost metallic "crack," compared to the tsuzumi’s softer "pon" sound. The ōkawa’s hourglass shape is slightly bigger and has a noticeable bump in the middle, unlike the kotsuzumi, which has a smooth middle section. The drum heads are stretched very tightly, with no extra space for adjustments. The ōkawa is played on the player’s left thigh, likely because of its large, heavy size, while the tsuzumi is played on the right shoulder.

The drum heads are made from thick, stiff horsehide from grown horses. The ōkawa’s drum heads must always stay dry, unlike the kotsuzumi’s heads, which must stay moist. To achieve the ōkawa’s high pitch, the drum heads must be as tight as possible, which is best done when they are dry. Before a performance, the drum heads are heated near a traditional Japanese furnace called a hibachi for at least an hour. Then, the player binds the drum heads to the ōkawa’s body using a thick, heavy rope and tightens them further with a thinner silk rope to help grip the drum. An ornamental hemp rope with long tassels is then placed on the drum. Because the drum heads are expensive—costing at least $1,000 per pair—the player must carefully track how often and how long the drum is used. If well cared for, the drum heads can last up to ten performances before showing wear and losing their sound quality and needing to be replaced.

Like the tsuzumi, the ōkawa is played with the player’s bare hands. Because the drum heads are stretched tightly, playing can be painful, so players develop calluses on their fingers for comfort. These calluses are occasionally cut with a knife to prevent them from growing too large. Many players use deerhide padding on their palms to protect their hands and improve the sound. They also wear fingerstalls made of multiple layers of Japanese washi paper stiffened with starch on their fingers.