Typhoon No. 19, named Hagibis, is still a couple of days from hitting land, but its potential for destruction is already being compared in the media with last month's No. 15, which wreaked havoc on large swaths of Chiba Prefecture in early September. At the peak, 930,000 households were without power -- a situation which a writer for Nikkan Gendai (Oct 5) inadvertently described as "shocking". At night neighborhood streets were left in the dark, and refrigeration units failed in both private homes and stores. Even worse, banks could not open and people could not access their accounts at ATMs. Nor could they use prepaid cards when the power was off.

So yes, reports Nikkan Gendai, it's probably a good idea to keep some money handy in case of power blackouts. One drugstore in Chiba, for example, managed to get open for business, but its electronic cash registers did not function, so it had no choice but to limit sales transactions to cash. At convenience stores and supermarkets the situation was the same. Cash was king; credit cards and prepaid IC cards were rendered useless.

"I myself, my parents and siblings live in Hokkaido, and I heard many tales of woe from people there following the big earthquake that struck last year," financial planner Hiromi Sekiguchi told the tabloid. "One simply can't rely on 'cashless' transactions in case of emergencies. You have got to keep some cash on hand."

How much cash? To be safe, for a household consisting of parents and two children, living expenditures for say, four to five days might come to "as much as 100,000 yen," says Sekiguchi. Of course some risk is entailed in holding onto that much money, since if the house were to be inundated by flooding or -- god forbid -- collapses, the money will be buried in the rubble. "If you're concerned, then make it half -- 50,000 yen," she says.

"In an emergency most shops might not be able to make change from larger bills, so it's better to keep at least part of the money in 1,000-yen notes or coins," Sekiguchi added.

Ryoichi Yoshida, a disaster consultant who survived the Great East Japan Earthquake and Tsunami in March 2011, advises that a person living alone should budget at least 2,000 yen per day for one week.

"If you've got extra money, then make it 3,000 yen per day, for seven days worth," he recommends. "In addition to 15,000 to 20,000 in your wallet, you ought to keep some extra in another place. And be sure to have some personal ID like a driver's license on hand too, as places like hospitals will accommodate you if can show some ID."

Should you run out of cash, the postal system will allow you to send cash through registered mails, which is likely to reach you fairly quickly as long as transport network is functioning.

The remarkable efficiency of the post office and parcel delivery services can generally be relied upon, even in cases of emergency. On the fourth day of the blackout, a drugstore in Kamogawa, Chiba Prefecture, said it was able to receive next-day parcel deliveries containing cash sent from within Tokyo's 23 wards.

The main thing to keep in mind is that the possibility of losing cash is probably far less than the likelihood that you'll be able to depend on your cell phone, ATM card, credit card and IC card for payments in the event the power goes off. And even if you can find an ATM that's operating, getting funds from it might involve waiting in a long queue for a considerable duration.

So consider cash a reliable safety net, the writer advises.

© Japan Today