Wondrous Soroban of Kaiu Haruko

The Wondrous Soroban of Kaiu Haruko was the first soroban of Rokugan. It was made of copper and coral.

Kaiu Wall
In 716, during The Maw's attack on the Crab lands, Kaiu Haruko devised the abacus to shorten the time needed to design the Kaiu Wall and to plan the logistics for its construction. In four days she accomplished the task, but before the wall was finished she had died in the fight. The abacus was held by her three students.

Lost
The soroban was lost at Hiruma Castle in the 10th century, when brought along to aid future fortifications once it was retaken.