The Information Systems section of a CPA office registered in Tokyo asked consultants of IF Computer Japan to convert a section of the Japanese tax system into machine readable and executable form.

The law-like text is published every year by the Japanese Ministry of Finance and is the body of rules that auditors should adhere to in complex tax cases.

The task in question, value estimation of not publicly traded stock of large companies is legally required under certain circumstances. It usually takes months for a CPA, with corresponding subtantial government condoned retainer fees.

IF Computer implemented a one-to-one mapping from the regulations into Prolog and developped the executive for these rules. The final system is designed to interface with standard accounting files.

System components are IF/Prolog for the legal knowledge and executive, OSF/Motif for the user interface, and machines from Sun Microsystems.

The CPA firm estimates the productivity increase at a factor of about 200. In addition to this immediate internal gain from two orders of magnitude in cost reduction, the firm expects to expand their business by better service: the system allows to simulate the fiscal impact of legal taxpayer choices. With traditional methods this was prohibitively time consuming.