Construct a Japanese Torii Gate for Your Garden

For some time, I had been thinking about building a Japanese torii gate for my garden. A torii gate marks the approach and entrance to a Shinto shrine. It is the division between the physical and spiritual worlds. Shinto is a native religion of Japan and was once its state religion. Probably the most famous torii is the one at Itsukushima Shrine located at Miyajima, near Hiroshima. Mine is a little more modest.

Step 1: Torii Components

After a bit of poking around on Google, I found that all torii gates are made up of three horizontal components:

- Kasagi: The very top beam of a torii gate. These beams can be straight or curved.
- Shimagi: A second beam directly underneath the kasagi in more complex forms of torii gates. Their ends are either straight or cut with an inward slant and the overall shape of the beam is that of an upside down trapezoid.
- Nuki: The secondary beam of a torii gate. On more complex torii gates, it is held in place by kusabi (wedges). This beam is always straight.

The other components of a torii are the:
- Hashira: The supporting pillars of the torii gate
- Gakuzuka: A centre post that connects the Nuki & Shimagi (optional)
- Kusabi: A wedge used to hold the Nuki in place (optional)
The Shimagi is usually placed below the lintels at a distance about equal to the diameter of the pillars.

The dimensions that I ended up choosing for my torii are somewhat of a trade-off given the thickness of my Hashiras (poles).

Step 2: Hashiras - the Posts

I wanted to build a decent-sized torii so I hunted around for some large posts to use for the Hashiras. I was hoping to use hardwood but found that they are scarce and expensive. I settled for treated pine posts, or Coppers logs as they are known as in Australia, and used 150mm x 3.6m lengths. Although the logs are relatively cheap, about $AU40 each from memory, you have to be selective when choosing them as many are shaped like bananas and others are badly knotted and split. I cut the logs to 3 metre lengths and used a hammer and chisel to start the mortise slots in either side of the posts and then used a large drill to drill through the posts and remove the bulk of the timber from the slots. I spent a bit of time hand-finishing the mortises with hammer and chisel and made sure that the Nuki would slide freely through the slots.

Step 3: Painting the Hashiras

The logs, by nature, have numerous splits and, although I had chosen wisely, there were many both small and medium sized splits in them. I filled and sanded the logs three times over to get a reasonably smooth finish on the timber and this was the most tedious part of the construction. Note the jig I used to hold the poles while I painted them. This allowed me to spin the poles while painting them with a roller.

Step 4: The Other Torii Components

For the Kasagi, Shimagi and Nuki, I elected to use second-hand oregon as I wanted to use wood that was dimensionally stable and was not going to either twist or warp with age. I have used new oregon in the past but unfortunately plantation "oregon", or what ever passes for oregon, is generally of poor quality, in my experience. I was luck enough to source all this timber very cheaply and only paid about $AU20 for the lot, a real bargain. I cut the timber to length and had it professionally dressed all round for $AU33. I cut the shape of the upper-most piece of timber, the Kasagi, by using a table saw to cut the parallel portion and used a hand saw to finish off the ends. Shown are, from left to right, the Shimagi (upside down), Kasagi and Nuki (upside down) all primed and ready for three coats of vermillion finish coat.

Step 5: Bolting It Together

The whole structure is bolted together with galvanised coach screws and washers, four long screws through the Shimagi into the end of the logs (two at either end) and one 100mm screw through either log to lock the Nuki into place.

Step 6: Raising the Torii Gate

Once everything was painted and ready for assembly, I dug two holes about 700 mm deep and 350 mm in diameter in order to concrete the structure firmly into the ground. I then filled the holes with about 100mm of dry rapid set concrete to form a base for the poles. The torii was then assembled on the ground in front of the holes and the coach screws done up snuggly. With the kind assistance of my cousin, we lifted the torii vertical and then carefully lowered the posts into the holes. We attached the temporary supporting braces via the top coach screws to torii in order to stabilise it while the concrete cured enough.

Step 7: Concreting It Into the Ground

I added enough water to the holes to mix the rapid-set concrete and then quickly leveled up the posts. I then ensured that the posts were standing vertically and that all looked good. This took some time to get it all true. We then mixed up the concrete and filled in the rest of holes. Note that the level of the concrete falls away from the poles in an attempt to stop water pooling around the poles and causing them to rot prematurely.

Step 8: Attaching the Kasagi

The Kasagi is decorative and is held in place by a piece of 30mm quad screwed into place with galvanised screws, at about 150mm centres, from the rear. The Gakuzuka is secured with a 20mm mortise and tennon joint at either end and I skew nailed it to the Nuki prior to painting.

Step 9: The Gakuzuka Plate

While I was in Japan a number of years ago, I bought a nice little brass plate inscribed with two characters that translate to fresh & fragrant and have attached this to the Gakuzuka using some small brass screws.