I posted this video a few days ago, “The Diamond Princess 14 Months Later”, and received this correspondence from an American who lived in Japan for 15+ years, speaks Japanese well, and still regularly follows Japanese language news reports, both print and broadcast.
Here are some bits and pieces of information I recall from watching and reading contemporaneous Japanese TV and print news reports about the Diamond Princess.
A Japanese doctor from Kobe (infectious disease prevention expert) visited the ship. He said infection control on the ship was really bad. More details in the linked articles. After the doctor shared his concerns on YouTube he was “uninvited” and left the ship. For a while (and maybe even continuing until now) his YouTube video disappeared.https://thehill.com/changing-america/well-being/prevention-cures/483630-japanese-doctor-calls-cruise-ship-quarantine; https://www.sciencemag.org/news/2020/02/scientist-decries-completely-chaotic-conditions-cruise-ship-japan-quarantined-after
A Japanese naval vessel (or a ship chartered by the Japanese Navy) docked close to the Diamond Princess. Japanese military personnel who assisted with medical matters on the Diamond Princess were lodged on that Navy vessel nearby. Per Japanese TV news, Japanese military infection control on the Naval ship and other places under the control was really strict and no disease transmission was ever traced to the Navy ship. A few basic details about the ship are here: https://www.tokyoreview.net/2020/04/self-defense-forces-japan-covid-19/
NOTE: Lots of Japanese civilian government agencies worked on the Diamond Princess and the Japanese military did not control the Japanese government efforts on the Diamond Princess. They only provided assistance.Per Japanese TV news, food delivery to staterooms provided lots of chances for the infection to spread.Testing on the Diamond Princess was limited and not everyone was tested frequently.
Per this article, on average each passenger was only tested once: https://www.nature.com/articles/d41586-020-00885-w
People who were released from ship with no infection were given a Japanese government document confirming the same.Overall, the Japanese population very healthy. The rate of obesity in Japan compared to the U.S. and Europe is extremely low. Furthermore, most Japanese eat a very healthy diet (lots of fiber, unprocessed foods, plenty of exercise, etc.). The infection rate is quite low compared to the U.S. in spite of the fact Japan has imposed relatively few limits on socializing, travel, etc. compared to the U.S. and Europe. As a result of the U.S. occupation and its changes to the Japanese constitution, the government in Japan has very little authority to tell people to stay home, etc.
The big concern in Japan is limited medical facilities. For 50+ years Japan has had a version of Obama Care and they have no surge capacity for something like the Wuhan Virus.Mask wearing in Japan, while customary and common, is not done carefully and I doubt it led to reduced infection. However, Japan is very clean and personal hygiene standards in Japan are very high across the board and undoubtedly that helps reduce infections. Please use and share this information as you see appropriate.