From myobi:

China, early Song Dynasty.

The setting is an era of absolute corruption, when bribery, torture, and threats were the normal way of doing business in the government. Then comes forth a young, new Official - Houjou - who challenges the corruption. Gifted by the Emperor with three beheading devices, he is charged with bringing justice back to the courts.

Based on the historical figure of Justice Bao (Chinese reading of the name), who was said to be an incorruptible official, this is a light-hearted romp through ancient China as he and his assistants work against the corruption that has become the norm in the Imperial Courts.

For more on the historical person and legends surrounding him, see:
http://en.wikipedia.org/wiki/Bao_Gong