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Translator's note: The center of the original woodcut illustration shows significant fading and loss of detail, likely due to wear on the original woodblock or paper aging.

The Water Jar Raft

shuiying original: 水罌; a flotation device constructed from large earthenware urns or jars

The Water Jar Raft is a specialized vessel designed for crossing rivers by utilizing the buoyancy of empty containers.

To construct this raft:

• Large ceramic jars original: 罌 (ying); bulbous storage jars with narrow necks are selected for their "empty bellies" to provide maximum displacement.
• These jars are arranged and secured beneath a wooden lattice frame original: 編木 (bianmu).
• A rope netting is added to bind the jars tightly together. This ensures the jars do not shift or scatter original: 使不散 (shi bu san) during the crossing, which would cause the raft to lose stability and sink.

The illustration depicts the raft floating upon stylized waves, featuring a series of vertical poles attached to the frame. These poles served as structural supports and defensive barriers for the soldiers positioned on top.

This technology demonstrates the ingenuity of the Song Dynasty military in repurposing common household items—large storage jars—into modular buoyancy units for rapid engineering projects.