This mounting project is for an upcoming katana.
It comprises the search for a very subtle design with enough hidden reinforcements inspired by the color of the Zen-like look of the photograph below. It shows a very light wood, which would be good for shirasaya, but not for a final tsuka.

Far from being unique, it was the photography itself that raised in me the need to further explore the soft look of it, combining the look with sturdiness and decorative elements that were also inspired by the octagonal shape of the shirasaya.
I have for long entertained the oar shape for an octagonal section. To accomplish the design I think that poplar wood is the most recommended wood due to its color and workability. It requires a good gluing.
This is mainly a saya mounting that has to survive some hard work and is not merely decorative hence the need for a strong protective saya protective lacquering, preferably matt.

Here is an example of the type of whitish poplar wood.

The new poplar wood approach still meets the aesthetical philosophy has been explained already. For workability it has to be poplar wood with a combination of horn and bone and some grooves.

1. Represents the schematics of the octagonal section, where the width has been compressed into an oval as can be seen by top and bottom sides.
2. Represents the wooden protrusion of the wood that embraces the habaki.
3. Here is a view of the horn koiguchi, 5 mm thick on top of the 3 mm bone.
Note: as the flared oar like saya modes towards the kojiri it will become thinner in a moderate way viewed from top.

This is a first alternative which differs from the second in the tsuka. A poplar tsuka, although visually nice here, is fragile. There is no wrapping to reinforce it.
In order to convey a mounting design that retains an overall feeling of the shirasaya photograph, yet having the necessary elements of a mounting, I designed a larger saya in vertical width, so as to both accommodate the subtle flaring of the beginning of the tsuka, but also creating a grip on the saya, both as a functional and decorative element, by:
a. the placement of a rounded horn kurikata at 5 inches (five) from the koiguchi.
b. the kurikata has a round bon inlay, as thin as 1 mm to create a stronger yet subtle visual reference.
c. the grooves start at about 1.5 inches from the kurikata and end at the same distance of the horn in the koiguchi, and have the equal number on the other end. These grooves can be just 1 or 2 mm deep.
d. the kashira has 5 mm thick horn, with a 3 mm bone ring between the kashira and the wood.
e. the kojiri shows how the section has been tapered and the flaring goes to a maximum of 10 cm at the end.
f. as a matter of coherence, I have created two mekugi which are in horn or delrin and the holes are surrounded both sides by a 1 mm thick bone inlay.

In conclusion, for a person of your talent and qualifications, I think this is a project well within your reach which final requires only that the wood is sealed with an extra matt lacquer. I believe the overall look is very low key with just the indispensable accents to make this an attractive piece.

This is an enlarged detail to allow for further analysis of details. Being naturally aikuchi, I would like to reinforce that the rendition of the kojiri and what would be the fuchi, places too much emphasis on the horn which should be 5 mm thick and the bond should be 3 mm.

In this version, the tsuka changes drastically to a more usable one. For this reason, the tsuba should continue to meet the koiguchi with the same section and be blackened. We will see how it works.

In this clickable illustration we can see the sword and the saya with a bokkuto type tsuka.
Note the tsuba meeting the koiguchi, meaning it is larger than the usual saya section. Just enough.
The tsuba should be as small as possible considering the presence of the seppa.

This illustration shows an incomplete tsuka. Only  the center part of the black silk katatemaki wrap with your beautiful fan menuki in brass if possible with a full white same wrap.
The fuchi-kashira are blackened mild steel to match the tsuba, and are very simple, like the ones you did before. I hope the menuki can be placed on top of the wrap through some piercing on the tsuka and glue.

This is the final and correct saya detail. Horn, bone, poplar at the beginning of the saya mouth, and the same applies in reverse order to the Kojiri: poplar, bone and horn in the end.
IMPORTANT: the Grooves in the saya should be on both sides of the kurikata as shown on version 1.

Finally, the kurikata is rounded as can be seen on a side view and on an end's rendition. The top view can be seen in the saya.

Tsuka length: 14 inches
Tsuka wrap: Katatemaki
Saya length: 32.5 inches
Metal parts: brass for menuki and seppa
Tsuba: 5mm thick blackened mild steel with a gloss finish.
Fuchi-Kashira: black with glossy finish.

- Brass Seppa 15.00
- Brass Fan Menuki - 50.00
- 17' Black Silk Ito - 50.00
- Large Knob Same - 60.00 is fine
- Steel Fuchi/Kashira chemical black (not glossy) - 50.00
- Steel Tsuba chemical black - 25.00
- Tsuka Core 60.00
- Same Wrap 30.00
- Battle Wrap Ito 60.00
- Boat oar Saya in Poplar with semi gloss clear Lacquer, Polished Bone and Horn Parts. No Grooves* - 250.00
TOTAL - $650.00

Project by Antonio Cejunior