Works well on shinken etc, but nihonto. hmmm should ask professional help.
How to Make Sokui;
1. Take a small amount of one- to two-day old cooked short-grain rice and place it on a clean, flat surface. A board works well.
2. Wet a strong, flat stick, such as a bamboo spatula and mash the rice.
3. Add a drop or two of water, and mash again.
4. Keep adding water as needed.
5. Continue mashing the rice until it becomes a sticky, glutinous mass with no lumps.
6. Gratulations ..You now have basic sokui.
How to Use Sokui
1. Use a small sliver of wood to spread a bead of sokui over the necessary area.
2. Press together the pieces to be glued. Hold them firmly in place using a cord, rubber band, or other similar device until dry.