Thread: Kintaro Yazawa Box with Key Hole Joint

Originally Posted by Mobyturns

I love the mystery and fully respect Kintaro Yazawa's playful teasing of potential imitators, such grace in acknowledging his own superiority as a maker whilst "seeing off any potential competition". At least he has passed on his knowledge and those guarded "commercial in confidence" trade secrets to his staff.

Another issue to consider here is the knowledge about how to construct that joint really is of curiosity or novelty value to us but it has significant commercial value and I might say adds a considerable premium to the unique work produced in Kintaro Yazawa's workshop and by him and his staff.

Nicely written, and I share your sentiments.

That is behind my reticence to disclose step 2:

• ethics of disclosing Yazawa's secret,
• buzz of joining Yazawa's secret society,
• wonder if I have a second solution, different from Yazawa's, and
• fear that I have a brilliant solution that does not work.

Yazawa runs a very small family business and his principal staff member is his son.

On intellectual property rights, my interest is absolutely non-commercial. I am not going to sell any boxes or license the design to anyone. But someone less scrupulous could copy - that is a real fear. No one wants to see every discount store and junk craft store selling cheap chinese Yazawa boxes. There is no law or ethical issue to stop me reverse engineering Coke, provided I do not attempt to sell it.

But from Yazawa's viewpoint the matter could be catastrophic. If his secrets leaked ... It is financially impossible for an individual to fight an intellectual property case against a major corporation - you will be bankrupted by legal expenses before you get near any court.

We were last in Japan shortly before lock down and noted that many restaurants, etc, had Hans Wegner Wishbone Chairs - a classic design, there almost always in a pale blonde timber with seemingly no visible finish. Phonetically, they were called sina-veigana - "China Wegner with Japanese pronunciation - the pirated version was so ubiquitous that it had acquired a common name. Very much doubt that Wegner was ever consulted.

Ah true, my suggestion is similar to that proposed by mic-d in Post 12 - I didn't look at that closely enough. By putting it together at 45deg I meant that when the piece with the keyhole shape is steam bent out of the way by 45deg then the joint could be slid together diagonally like an impossible dovetail goes together. But, from what you say this has been tried quite some time ago and didn't work so back to the drawing board!

Originally Posted by mannetje

Ah true, my suggestion is similar to that proposed by mic-d in Post 12 - I didn't look at that closely enough. By putting it together at 45deg I meant that when the piece with the keyhole shape is steam bent out of the way by 45deg then the joint could be slid together diagonally like an impossible dovetail goes together. But, from what you say this has been tried quite some time ago and didn't work so back to the drawing board!

Not my proposal in post 12, just an image I found on the interwebs. I thought this was highly unlikely.

If I find a solution to this and can make a joint, there's no way I'm telling anyone...

Originally Posted by GraemeCook

Originally Posted by Mobyturns

That is certainly one way to imitate the look but there are no advantages structurally over a plain finger joint ...

MT, Intriguingly your statement is both true and false.

It does not have a structural advantage over a plain finger joint because it actually reduces the glue surface area.

But, conversely if you assemble the joint dry then it will just pull apart. But if you insert the dowels then the joint locks, and you cannot disassemble it without removing at least one set of dowels.

Originally Posted by GraemeCook

MT, Intriguingly your statement is both true and false.

It does not have a structural advantage over a plain finger joint because it actually reduces the glue surface area.

But, conversely if you assemble the joint dry then it will just pull apart. But if you insert the dowels then the joint locks, and you cannot disassemble it without removing at least one set of dowels.

I disagree.

Your contention that the dowels "lock" the joint (in your proposed method) is only true IF the dowels extend past the joint into the stock. Then it is effectively a pined joint, not really any different to a pined mitre joint etc.

Your method also raises the small matter of the joint, hole & dowel alignment wrt to being flush with the inside face of the stock. I agree that the joint could be offset relative to that face creating an illusion of a standard finger joint and "keyhole" but seems way more complex than it needs to be.

However on appearances that is not how the original is constructed.

It's head scratcher and one that I hope Kintaro keeps a mystery.

Originally Posted by Mobyturns

I disagree.

Your contention that the dowels "lock" the joint (in your proposed method) is only true IF the dowels extend past the joint into the stock...

It is not necessary for the dowels to extend past the joint (as shown in my drawing) to lock the joint.

Simply having the short dowels in place stops the fingers from being slid sideways. This locks the joint.

But this is not the solution to the conundrum - just part of the process of working towards that solution.

Originally Posted by GraemeCook

It is not necessary for the dowels to extend past the joint (as shown in my drawing) to lock the joint.

Simply having the short dowels in place stops the fingers from being slid sideways. This locks the joint.

But this is not the solution to the conundrum - just part of the process of working towards that solution.

Actually Graeme (although discussion on these loose dowels (tenons) is moot, because Franklin's reply was taken out of context in post 29 and we've gone down a rabbit hole we never needed to), MT is right that the dowels placed in afterwards don't lock the joint unless they continue into the stock. Look at pulling the yellow board forward to pull the joint apart and look at the yellow finger that touches one of the dowels. There is nothing locking the finger to the dowel, it can simply slide away from the dowel. If the dowels were drilled into the stock of the yellow board, the dowel would then have to move with the yellow board and it truly would have been locked into the fingers of the orange board.

Just to reiterate for anyone who only has a cursory glance at the thread, Franklin's idea of drilling in seperate dowels was not meant as a solution to the joint but only as a way of understanding how the real joint may go together. Trying to make it out as anything but that is just a waste of time.

Mic-d is spot on. I'm sorry if I've confused the issue.

I imagined one could construct the pieces that way unassembled gluing the dowels in place. I would then start carving away bits of the joint to see how it might be possible to pare them down to pieces that might slip together.

I haven't had the time to work on it, but if i did I think I'd be trying several ways, cutting mitres into some fingers and curves into others to see what might work.

My brain these days seems to work best with my hands fiddling rather than working in 3D imagination.

I don't believe you have confused the issue with the post installation of the dowels. As you say one way to explore the (possible?) construction methodology.

When you read the history of Japanese construction joinery - Sashimono - it relied heavily upon the joinery techniques themselves with no iron, or other metallic, mechanical fasteners or glue for joint security & strength from immaculate joinery - tsunagi!

Those skills and techniques transferred to cabinetry and other small joinery - no glue, just the mechanical strength of the joint, some very clever design, immaculate craftsmanship and assembly.

There is of course one way to discover how the joinery was done, purchase a box and disassemble it! but the Chinese have probably already done that.

Originally Posted by Mobyturns

When you read the history of Japanese construction joinery - Sashimono - it relied heavily upon the joinery techniques themselves with no iron, or other metallic, mechanical fasteners or glue for joint security & strength from immaculate joinery - tsunagi!

So true; I love sashimono and am fascinated by it. Sashimono evolved from an adaptation of temple architecture.

Japan, like New Zealand, is on the shakiest part of the ring of fire; earthquakes are a regular occurrence. Temples are mainly built from timber on the post and lintel system with intricate self locking joints on a massive scale - think 500x500 mm beams, and larger which are still standing after 1,000 years whereas modern buildings and freeways have been flattened by earthquakes. The temples flex and bend with the quakes. But those old buildings are totally dismantled every 200 years, and every worn or imperfect component is replaced and then it is reassembled. So that 1,000 year old building is quite like great grandad's axe! That philosophy and technique has been transferred to sashimono.

There is of course one way to discover how the joinery was done, purchase a box and disassemble it! but the Chinese have probably already done that.

Nah. You cannot buy the boxes at Target or Bunnings, so the chinese haven't done so.