Zouma Xiao (走马销): The Sliding Key That Lets Chinese Furniture Come Apart
Zouma xiao · 栽榫 (planted tenon) · 挂楔
A Ming couch bed has heavy railings on three sides, yet it can be lifted apart and moved. No screws, no glue at the railings. The secret is a small block of wood with a big name.
The zouma xiao, literally “galloping-horse key”, is a dovetailed pin that drops into a slot and slides to lock. Slide it back, and the parts come away.
- Chinese
- 走马销 · zǒumǎ xiāo
- Also called
- 栽榫, 桩头, 挂楔
- Joins
- Parts that must come apart
- Found in
- Couch-bed railings, screens, thick board panels
- Signature parts
- Separate pin · wide-and-narrow mortise
How it works
A planted pin
Parts that are taken apart wear their tenons. So the pin is made of a separate piece of wood and planted into one member. If it wears or breaks, you replace the pin, not the whole railing.
Wide end, narrow end
The pin is narrow at its root and wide at its tip. The mortise in the other member is wide at one end and narrow at the other. Drop the pin into the wide end, push the part along, and the pin’s wide tip slides under the narrow end. It can no longer be lifted out.
Taking it apart
Knock the part back the other way, the pin returns to the wide end, and it lifts free.
How it's made
Step 1Plant the pin
Make the pin from a separate piece of hard wood and plant it in one member.
Step 2Shape the pin
It is narrow at the root and wide at the tip.
Step 3Cut the slot
Cut a mortise in the other member, wide at one end and narrow at the other.
Step 4Drop it in
Lower the pin into the wide end of the slot.
Step 5Slide to lock
Push the part along so the pin moves into the narrow end.
Step 6Take it apart
To dismantle, slide it back and lift.
Variations
Couch-bed railings
The classic place: between the railings, and between the side railings and the bed frame.
Board joints
Thick boards can be joined edge to edge with zouma pins.
In museum collections
Minneapolis Institute of Art
Related joints
Wedged Scarf Joint (楔钉榫)
Curved pieces lapped with hooked tips and locked by a tapered key through the middle: how a horseshoe chair arm is built.
Dovetail Joint (燕尾榫)
A tenon wider at the tip than at the root, so it can’t pull out: found in boxes, drawers, tables and temple beams.
Giant’s-Arm Brace (霸王枨)
An S-curved brace from the leg up to the underside of the top, hooked into the leg and locked with a wedge.
Questions
What is a zouma xiao?
A sliding wooden key used in Chinese furniture that has to come apart. A dovetailed pin drops into a wide-and-narrow slot and slides to lock.
Why is the pin a separate piece?
Joints that are taken apart wear out. A separate pin can be replaced without ruining the part it sits in.
Where will I find it?
Most often in the railings of a couch bed (罗汉床), and in screens.