Jiatou Sun (夹头榫): The Bridle Joint Behind Ming Recessed-Leg Tables
Jiatou sun · Clamping-head joint
The long, quiet tables of Ming China, painting tables and altar tables, stand on legs set in from the ends. Where each leg meets the top, it rises past a long apron and a pair of shaped spandrel heads.
Inside that junction is the jiatou sun, the elongated bridle joint. The leg is slotted at the top and literally clamps the apron, so the whole underframe becomes one rigid ring.
- Chinese
- 夹头榫 · jiātóu sǔn
- Joins
- Leg, apron, spandrel heads and top
- Found in
- Recessed-leg tables: painting, altar and side tables
- Signature parts
- Slotted leg top · apron · spandrel heads (牙头)
- Look
- The leg stands proud of the apron
How it works
Borrowed from buildings
Wang Shixiang traced the joint to the Northern Song, when furniture makers borrowed from timber-frame buildings, where a column top is slotted to clamp a bracket. On tables the clamped pieces became one long apron, and spandrel heads were added beneath.
The slot
The top of the leg is sawn open. In the standard form the slot is long enough to clamp both the apron and the spandrel heads. The leg then tenons into the underside of the top.
Why it works
The apron gives the leg a much bigger grip on the top, so the angle between leg and top can’t easily change, and the weight of the top is spread evenly to all four legs.
How it's made
Step 1Slot the leg
Saw an open slot down the top of the leg, deep enough for the apron and the spandrel heads.
Step 2Tenon the leg top
Leave tenons on the leg top to go into the table top.
Step 3Shape the spandrel heads
Cut the spandrel heads to fit in the slot below the apron.
Step 4Drop in apron and spandrels
Lower the spandrel heads and the apron into the slot.
Step 5Set the top on
Fit the top over the leg tenons.
Step 6Check the look
The leg stands proud of the apron and spandrels on the outside.
Variations
Slot clamps the apron only
The spandrel heads are thin upright pieces set into grooves on either side of the leg.
Grooved, not slotted
The leg is only grooved and the apron is in sections. Wang called this showy but weak; it spread after the mid-Qing.
In museum collections
Cleveland Museum of Art
Cleveland Museum of Art
Related joints
Inserted-Shoulder Joint (插肩榫)
The leg is cut to a pointed shoulder that the grooved apron straddles, finishing flush; the heavier the top, the tighter it grips.
Long-and-Short Tenons (长短榫)
Two tenons at right angles on the top of a leg: a long one for the long side, a short one for the end.
Baojian Joint (抱肩榫)
The hidden lock behind every waisted Ming table corner: a mitred shoulder, a triangular tenon and a tapered pin.
Questions
What is a jiatou joint?
The leg-to-top joint of Chinese recessed-leg tables: the leg top is slotted to clamp the apron and spandrel heads, and tenons into the top.
How is it different from the chajian joint?
In a jiatou joint the leg stands proud of the apron. In the chajian joint the leg is cut to a V shoulder and finishes flush with it.
Where does it come from?
Wang Shixiang traced it to Northern Song builders, who borrowed the slotted column head from timber architecture.