The ritual starts the day before the deceased's first birthday after his death. It is intended to release his soul from the body, to release it from the grave. He is being born again.
Take a thin piece of wood, such as a roof shim. Paint on it all the names by which the deceased was known in white paint. The size of the wood should be related to the dead man's body in some way, such as a palm or a span, but if this is not possible, the size of a shoe can be used to determine a measurement of the dead man.
A leather cord is wrapped around the wood. Best is pig leather; second best is any other kind. If a leather shoe lace of the deceased is available, that is wonderful.
A trench is dug, about two inches longer and wider than the wood piece (or a knuckle length of the deceased, if that is known). If possible it is dug into the grave; if not, then into the yard of the deceased's home, as close to the least-used door as possible. The wood is put into the trench, which is then filled in. A cairn of small stones is built on it, at most a dozen; six or seven is better.
Before dawn on the next day, a small brazier such as a hibachi is set up next to the hole. A small amount of kindling-sized wood is put into the brazier, along with tinder; if possible, use a kind of wood different from that of the tablet.
During false dawn, dismantle the cairn, putting the stones around the hole. Dig up the wood. Put the stones into the hole.
Paint over the names with red or yellow paint.
When the sun begins to rise, move the brazier over the hole and light the fire. Unwrap the leather and put it on the fire; when it has caught, put the tablet on top it and the other wood. Pour either melted clarified butter (melt it with another fire; a pot of sterno can be put next to the brazier for this) or corn oil on the tablet, avoiding pouring it on the other part of the fire. If the deceased drank hard liquor or liqueur, pour some of that on as well.
Let the fire burn until all the wood has burned. Let it die down and remove the brazier from the hole. (Use fire gloves). Let it cool. Meanwhile, fill the hole.
When the ashes are cool, transfer them to a wooden bowl. Crunch and stir them with a length of wood. Bring them to the grave and scatter them on it. Throw the bowl and wood away.
This is a theoretical ritual, written as an exercise in ritual construction. I've tried to use universal symbols. The theology behind it (not one I personally believe in) is that the soul is linked to the body and must be released from it.
What has been done here is that the tablet has been identified with the body of the deceased through the names and the leather and being buried. It can be directly identified with the body in the grave by being buried there, or indirectly by being buried in the deceased's yard; it is put next to the least-used door because the ritual will be one of going out, but there is a desire to separate the deceased from the home.
White paint is used because white being the color of the dead.
The leather cord represents being bound by the body, the pig being a traditional chthonic animal.
You want to use the smallest amount of kindling wood possible, in part because you don't want the fire to last too long, and in part because you want the ash of the tablet to be mixed with as little other wood as possible.
The stones are placed in the hole as replacements for the soul.
Repainting the names in red or yellow transforms them from the color of death into the color of the sun or fire, the enlivening warmth.
The butter or oil, and the liquor or liqueur, feeds the tablet, and thus the dead man's soul.