Two Mie Prefecture towns that had vowed not to join the national resident registry network made an about-face Friday morning and connected to the system.
The town of Futami, with a population of about 9,300, connected to the network because it has set new local rules to deal with problems such as the abuse or leak of personal data shared through the network, a town official said.
The other town, Obata, which has a population of about 18,400, also joined the network for the same reason, an Obata official said.
As a result, there will be only four holdouts not fully integrated into the system: Kokubunji, in western Tokyo; Suginami Ward, Tokyo; Yamatsuri, Fukushima Prefecture; and Yokohama.
Yokohama -- Japan's largest municipality with a population of about 3.45 million -- shares resident registry information via the network only if residents allow their data to be included.
Futami set guidelines Thursday requiring the municipality to cut itself off from the network in the event of a security leak.
The guidelines also require the town to ensure no data is tampered with, and town officials who access the network will have their data recorded.
The registry network was launched Monday.