"The rods for calculation are made of bamboo, two fen wide and three cun long. The positive rods have three ed…
"The rods for calculation are made of bamboo, two fen wide and three cun long. The positive rods have three edges, totaling 216 pieces forming a hexagon, belonging to the Qian. The negative rods have four edges, totaling 144 pieces forming a square, belonging to the Kun."