These are the relevant references from the Books where Bone Gambling is mentioned.
I make no pronouncements on these matters, but report them as I find them.
Arrive at your own conclusions.
I wish you well,
Imnak and I sat across from one another, both crosslegged. He dropped a tiny bone to the fur mat between us.
Each player, in turn, drops a bone, one of several in his supply. The bone Imnak had dropped was carved in the shape of a small tabuk. Each of the bones is carved to resemble an animal, such as an arctic gant, a northern bosk, a lart, a tabuk or sleen, and so on. The bone which remains upright is the winner. If both bones do not remain upright there is no winner on that throw. Similarly, if both bones should remain upright, they are dropped again. A bone which does not remain upright, if its opposing bone does remain upright, is placed in the stock of he whose bone remained upright. The game is finished when one of the two players is cleaned out of bones.
I dropped the tiny carved tabuk which was mine, that which was my piece in the game. It did not land upright.
"I have won," said Imnak.
I had won her use in the bone gambling, her use as complete slave, until I chose to leave the tent.
"You have won in the bone gambling before," she said. "Why did you wait so long to select me to serve you? Am I not pleasing to a master?"
"You are acceptable, Slave Girl," I said.
"I will try to be pleasing," she said.
Before, when I had won in the bone gambling, the dropping of the tiny figures of bone and ivory, I had, of intent, selected blond Thimble, whom I would, in the tenure of her service to me, name 'Barbara', putting that name on her, though then of course as a slave name.
"I wanted to let the little pudding named Audrey simmer," I told her.
"You were cruel," she said.
Imnak, since he had acquired Poalu, had scarcely glanced at his two white-skinned slave beasts. It was not that he had meant to be cruel. It was rather that he was simply otherwise occupied. And even had he thought of it, their deprivation would not have been of concern to him, for they were only animals.
Both girls would kneel to one side, stripped, awaiting the outcome of the bone gambling. Sometimes I won, and sometimes Imnak won. When Imnak won he might have the use of Arlene, if he chose, or a tabuk steak. Not unoften, to my amusement and Arlene's outrage, Imnak would select the steak. As I explained to her this was not because there was anything intrinsically lacking in her but because Imnak had eyes only, or generally, for Poalu. He was usually anxious to get his little red slave into the furs. His little slave was forced to compensate him well, indeed, a thousand-fold and more, for the frustrating years of her freedom and arrogance. Interestingly, too, she did not seem to mind.