
The lattice has been snapped together, and the pieces that form the center of the blossoms are being added
The lengths of kumiko are at last joined into a lattice of triangles. The aim now is to fill in each of the triangles with smaller pieces of cedar to form the sakura—or cherry blossom—pattern.
The first pieces to go in form the center of the blossoms. Using a chisel and a small paring guide, the end of a length of cedar is pared away to a precise angle, the final length is marked, the piece is sawed, and the second end is pared to achieve the final length and a smooth finish. These tiny lengths are then pressed into the corners of each triangle.

The excess length of the kumiko lattice is trimmed with a pull saw

Thicker pieces frame the thinner kumiko grid. Here, the frame joints have been cut, and their edges chamfered.
To lend the grid a crisp, finished look, a slightly thicker frame, also made from yellow cedar, is added. In order for the grid to fit into a square frame, the excess length on each kumiko strip must be removed. This is done by carefully sawing through the midpoint of the outer joints, taking care to make a square cut.
Once the grid has square corners and the frame pieces have been joined and their edges chamfered, the entire assembly is brought together:

The kumiko grid, framed
This is where the magic happens.
The petals of the cherry blossoms—ultimately appearing like three spokes inside each triangle—are formed from two thin pieces of cedar. The first piece makes up two of three spokes, and therefore must be cut and hinged open to allow its two halves to be set at an angle to one another.
To accomplish this, a small length is squared at both ends, marked at its center, and then carefully sawn across its face until only the faintest whisper of wood remains on the opposite face. The goal is to leave as many wood fibers as needed to keep the piece intact, but so few that it may be gently bent open. When all goes well, sunlight glows through the hinge.

The hinge piece, ends squared, marked at its center

The hinge piece, sawn across its face, just shy of being cut in half

Sunlight glows through the hinge of a petal piece
The second petal-forming piece is again a small length of cedar. One end is made square, and the other is cut to form a spear point that fits into the space created when the hinged piece is pried open.

A sharp chisel pares one end of the simpler petal piece. The piece is flipped and pared at the same angle across half its thickness to form a spear point.

The resulting spear point.
To assemble the petals, the hinged piece is opened and placed into a triangle in the grid, care being taken to align and position its lengths evenly. The spear point piece is then pressed down until it is flush with the surface of the grid. The pressure of the pieces against each other holds them in place.

A spear point piece is fit into a hinge piece to form the petal of a cherry blossom
This is then repeated for every triangle.

A fine-toothed saw makes the first angled cut into a group of kumiko pieces
With the kumiko strips precisely thicknessed, I gather them into small bunches in order to cut the joints that will hold them together in a diamond-shaped lattice.
Three strips cross each other at every meeting place. To make this work, one-third of each strip is kept intact and the other two-thirds removed. The third left intact must be positioned at a different height in each strip so that it may pass through the joint unobstructed. Because the third left on the bottom or top of a strip is created the same way, i.e. by removing two-thirds of the depth of the strip, two of the strips may be cut in the same manner. A second type of cut, in which the middle third of a strip is retained, is required to complete the joint.
First, one group of strips are cut at regular intervals, two saw cuts defining the edges of each joint. The strips are then cut at the same intervals, this time in the opposite direction, so that the new saw cuts form x’s with the previous ones.
For the second type of cut, the same angled cuts are made at the same intervals, but their depth is restricted to one-third the height of the strip. The strips are flipped, and the cuts repeated.
In either case, the waste between each pair of saw cuts is removed with a small chisel.
At the end of this process, I’m left with small armies of two different types of strips. The next step is to put them all together to form a lattice and start filling in the resulting triangles.