Mantou Sun (馒头榫): The Column-Head Tenon of Chinese Timber Buildings
Mantou sun · Bun tenon
In a Chinese timber building, a heavy beam sits directly on top of each column. What stops it from sliding?
A small block on the column head, named after a steamed bun: the mantou sun.
- Chinese
- 馒头榫 · mántou sǔn
- Joins
- Column head (or king post) to beam
- Found in
- Timber-frame halls, pavilions, houses
- Size
- About 1/4–3/10 of the column diameter, slightly tapered
How it works
A short square tenon
The top of the column (or a king post) is cut to a short square tenon, its length, width and thickness about a quarter to three-tenths of the column diameter, slightly tapered with the top edges eased.
Into the beam
It goes into a socket (海眼) cut in the underside of the beam. The beam’s weight holds it down; the tenon stops it sliding sideways.
How it's made
Step 1Cut the tenon
Cut a short square tenon on the column head.
Step 2Size
About 1/4–3/10 of the column diameter.
Step 3Socket the beam
Cut a socket in the underside of the beam.
Step 4Lower the beam
Lower the beam onto the column.
Step 5Located
The tenon stops the beam sliding.
Step 6Hidden
Once in place it can’t be seen.
Variations
On king posts
The same tenon tops king posts (瓜柱) under ridge beams.
Related joints
Column-Foot Tenon (管脚榫)
A short round tenon at the column foot drops into a socket in the stone base, so the column can’t shift.
Clasping-Head Tenon (箍头榫)
The beam drops into a slot across the column head and runs on past it; the head beyond “clasps” the column.
Big-In, Small-Out Tenon (大进小出榫)
Part blind, part through: a big tenon enters, a small one shows. It lets two stretchers share a leg without weakening it.
Questions
What is a mantou tenon?
A short square tenon on a column head fitting a socket under the beam.
How big is it?
Traditionally about 1/4–3/10 of the column diameter.
Why the name?
Its short, rounded-off block shape is likened to a steamed bun.