18 by 9 metres: the centre line under the net (white, between the net's edges), the attack lines 3 metres from it with the front zone a shade apart, the attack lines' five-dash extensions beyond the side lines, the service zone's two marks behind each end line, and the antennae.
The picture above was drawn when the docs were built. The script below draws it again with the published package.
import { drawKyogijo } from "@johnmorrisdotca/kyogijo-stadiums";
const svg = drawKyogijo({ sport: "volleyball" });
This page imports the package from jsDelivr (major version 0), which serves only versions that have been published to npm. A feature added after the last release is not in it: the page then keeps the picture above and says why. The docs were built from version 0.6.1.