榫卯Chinese Joinery
Frame corner joints
闷榫
mèn sǔn

Men Sun (闷榫): The Fully Hidden Dovetail of Chinese Thick-Board Tables

Men sun · Blind mitred dovetail · 暗榫

Some Chinese low tables are made of just three thick boards: a top and two board legs. At each corner you see one clean diagonal line and nothing else.

Inside is a men sun, literally a “stuffy” or closed-in tenon: dovetails completely hidden behind a mitre.

Chinese
闷榫 · mèn sǔn
Also called
暗榫; modern woodworkers say 全隐燕尾榫
Joins
Thick boards at a corner; thin drawer sides
Found in
Board-leg kang and side tables, fine drawers, small boxes
Signature parts
Mitred outer skin · hidden dovetails
Drag to rotate. Slide to take the joint apart, or press Assemble to watch it go together.

How it works

Three thick boards

Wang Shixiang describes kang and side tables made of three boards up to 4–5 cm thick. Where the top meets the board legs, every example he saw used a men sun: after closing, only one seam shows and all the joinery is hidden.

Dovetails inside

The corner is mitred on the outside. Behind the mitre, dovetails on one board fit sockets in the other, so the boards can’t pull apart.

Drawers too

The same idea, made finer, joins very thin drawer sides in small pieces such as document boxes and mirror stands. It is the most refined of the board-corner joints, above the open dovetail and the half-hidden one.

How it's made

  1. Mitre the corner
    Step 1

    Mitre the corner

    The two thick boards meet at a mitre.

  2. Cut hidden dovetails
    Step 2

    Cut hidden dovetails

    Dovetails are cut inside the mitre, short of every outer face.

  3. Cut the sockets
    Step 3

    Cut the sockets

    Matching sockets are cut inside the other board.

  4. Slide together
    Step 4

    Slide together

    The boards are slid together.

  5. Skin covers all
    Step 5

    Skin covers all

    The mitred outer skin hides every dovetail.

  6. One seam
    Step 6

    One seam

    Closed up, only a single seam line shows.

Variations

Through dovetail

Both faces show the dovetails; Wang says only rough folk pieces used it on drawers.

Half-hidden dovetail

Shows on one face only.

Hooked mitre

A quicker look-alike for aprons that can work loose with age.

Questions

What is a men sun?

A corner joint for boards with dovetails completely hidden inside a mitre, so only a seam line shows.

Where is it used?

Thick-board kang and side tables, and the drawers of fine small furniture.

How is it different from a normal dovetail?

A normal dovetail shows on one or both faces; a men sun shows nothing but the mitre.

Further reading
  1. Wang Shixiang, 家具结构之结合 (excerpt), Sina Collection
  2. 榫卯结构, 科普中国
  3. 王世襄手绘榫卯结构 85 种 (list), 美篇