So, Japan’s 1,000-year-old cheese that’s back in fashion due to COVID-19 pandemic

A year ago, on February 27, 2020, Prime Minister Shinzo Abe requested that all schools in Japan shut down until early April to stop the spread of COVID-19.
And of course, by the following week, most schools across the country shuttered their doors.
However, one of the biggest buyers of Japanese agricultural products is the school lunch program, which feeds elementary and middle school students across the whole country. To clarify, around 10% of all domestic food production goes to school lunch, which usually emphasizes local or domestic products and, besides feeding the students, lunch at Japanese schools is frequently used as a teaching moment, to educate them about traditional regional dishes as well as locally produced foods.
Especially dairy farms felt the blow right away, a few pleaded to the public to buy more milk, both to evade financial trouble and so that their cows, who have to be milked every day, wouldn’t suffer.
People quickly jumped to help, but the obvious question soon arose: what to do with so much extra milk? Families could give milk to their kids with lunch at home, but adults in Japan don’t drink a whole lot of milk, although they do consume other dairy products, such as yogurt and cheese.
That has led to people looking for new ways to use that milk, which has brought back a millennium-old Japanese food called 蘇, or “so”, an ancient sort of “cheese.”
It’s not quite certain where its modern trend started, but along with recipes for desserts that used excess milk, a craze for making so took off in early March.

So is a Japanese dairy product from the Nara (710–794) and Heian (794–1185) periods, when the influence from China and Korea was at its strongest, but its history goes all the way back to the Asuka era, which started in 538. The aristocrats that ruled the land at the time eagerly absorbed culture and technology from the mainland, including the consumption of dairy products and dairy farming, which didn’t exist in Japan at the time.
Historical records say that it was popular with the nobility, and its one and only ingredient is milk.
Either way, Heian-era documents list several dairy products, including raku, which may have been butter or a kind of condensed milk, and daigo, which may have been a cheese or a type of ghee. However, no records remain for how dairy products were made, with one exception: So. The Engishiki, a book of laws and customs that was written mostly in 927, notes that it was made by cooking down milk to one tenth of its volume, and It was exquisite enough to be deemed suitable for presenting to the emperor.
In 1185, after a long, bloody war for control of the land, the warlord Minamoto no Yoritomo established the Kamakura Shogunate, kicking off the era of the samurai, which lasted (a couple of interruptions apart) until 1868.
The samurai were not interested in cows or dairy, as they were far more interested in breeding lots of horses to use for battle. And, as a result, dairy farming in Japan virtually disappeared, until the start of the modern era in the Meiji period (1868-1912).

A few online cooks and history buffs have been trying to make so for some years, as part of a general renewed interest in Japanese history and how people lived in the past.
Homebound people recently started posting recipes and pictures for so on social networks, discussing how to cook it and reporting back on how it tasted.
After hours of stirring and chilling, milk becomes cheese-like.
If you want to try your hand at making so, cook down non-UHT pasteurized full-fat milk over low heat, stirring it occasionally, until it forms a mass. Form the mass into a block, cover in plastic wrap, and refrigerate until firm….