Hakuō wanted to ensure that only trained specialists performed vaccinations so that parents would not lose confidence in the treatment and make their children's bodies available for vaccinations. A few weeks after his return to Fukui (1850, 1/17), he wrote to specialists of Dutch medicine in other nearby towns and territories with an offer to share the vaccine. Physicians from Fuchū (a subfief of Fukui domain) had received a transmission upon Hakuō's reentry to Fukui. In subsequent weeks, colleagues from Toyama (Toyama, a branch domain of Kaga), Kanazawa (Kaga domain), Tsuruga (Obama domain), Sabae (Sabae domain), Ōno (Ōno domain), Daishōji (branch domain of Kaga), Maruoka (Maruoka domain), Kanazu (Fukui domain), and Katsuyama (Katsuyama domain) came to Fukui with children in tow to carry vaccines home through their bodies. Before vaccination, they had to swear an oath at the domain office that they would observe ethic  and technical requirements.

For a translation of the oath, click here.

The newly minted vaccinators all joined the vaccinators' society (sha) and formed chapters (so-called shachū) in their respective towns. Initially, each chapter had only a handful of members, but together, the chapters formed a professional organization across domain borders that could provide retransmissions. Other functions of the organization included the sharing of information and suppression of uncontrolled transmissions. An autonomous, self-regulating network of medical professionals was thus taking shape without significant input from domain governments. At the same time, collaboration with domain leaders was one of the network's most important functions.