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 made by the kotsuzumi. The ōkawa is bigger than the kotsuzumi, and its drum head has a plain, leathery appearance instead of the more decorated head of the kotsuzumi. The sound of the ōkawa is higher and sharper, like a dry, almost metallic "crack," compared to the tsuzumi's softer "pon" sound. The hourglass shape of the ōkawa is slightly larger and has a noticeable knob in the center, unlike the kotsuzumi, which has a smooth middle. The drum heads are stretched very tightly, so they cannot be adjusted further. The ōkawa is played on the player's left thigh, possibly because of its larger, heavier 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 remain moist. To achieve the higher pitch of the ōkawa, the drum heads must be as tight as possible, which happens best when they are dry. Before a performance, players often heat the drum heads near a traditional Japanese furnace called a hibachi for at least an hour. When ready to play, the player tightly binds the drum heads to the ōkawa using a thick, heavy hemp rope. A thinner silk rope is then used to further tighten the binding and help the player grip the drum. An ornamental hemp rope with long tassels is also tied to the drum for decoration. 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, at which point they must be replaced.

Like the tsuzumi, the ōkawa is played with the player's bare hands. Because the drum heads are stretched very tightly, playing the drum can be painful, and players develop calluses on their fingers to play comfortably. These calluses must be trimmed with a knife if they become 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, hardened with starch, on their fingers.