"The trigger for this was that with the Ukraine invasion going on, and this situation in which we're wondering when or if a North Korean missile will fall, I started thinking if it might be good to have a shelter."
The Morohoshi family has joined a small but growing number of Japanese who are taking security into their own hands.
"When it comes to protecting lives in an emergency, this room (the shelter) is like buying safety for my family. I think it's absolutely worth it."
Some reached out to Nao Engineering, which has been selling its Crisis-1 shelters since December 2021, but saw a surge in inquiries after Russia's invasion of Ukraine in February.
Yoshimitsu Koyano is the company's senior managing director.
"There is talk about Russia actually using nuclear weapons. Chinese missiles have landed inside the EEZ (Japan's maritime "Exclusive Economic Area"), and the number of North Korean missile incidents has been growing. So among Japanese people overall, this has triggered the feeling that they'd like to have a bomb shelter at home, and as a result orders have risen."
Nao's shelters are about the size of a large walk-in closet.
Made of iron, they have lead plating to withstand all but a direct hit from a missile or nuclear blast.
And an Israeli-made filtration system will keep out radiation or dangerous gas.
But that protection comes at a price.
The shelters, custom-built at Nao's factory in Ibaraki prefecture, north of Tokyo, cost 6 million yen ($44,000) before installation expenses.
Even after more than 70 years, memories of intense bombing during World War II remain in Japan, including the only atomic detonations in combat.
And with North Korea said to be preparing for its first nuclear test since 2017, and Russian President Vladimir Putin threatening to use "all means" in his nation's defence, some fear the threat is becoming more urgent.
