A person living alone in Japan can start with nine litres of water and nine eating occasions for three days; the fuller seven-day target is about 21 litres and 21 eating occasions. Japan's Ministry of Agriculture, Forestry and Fisheries (MAFF) recommends at least three days, preferably one week, of food per household member. Its approximately three litres per person per day covers drinking plus cooking—not three litres of drinking water followed by another three for cooking. Sanitation and particular health needs may need additional water.
You do not need to convert a small Tokyo or Osaka flat into a storeroom. The more workable method is rolling stock (ローリングストック): keep slightly more of the shelf-stable groceries you normally eat, use the oldest and replace it on your next shopping trip. But reserve the first day for meals that require no flame, power or tap water. A damaged home or municipal evacuation order overrides the pantry plan.
The amounts: three days first, a week as the stronger target
| Household and duration | MAFF-based water at ~3 L/day/person | If buying 2 L bottles | Breakfasts + other meals |
|---|---|---|---|
| One adult, 3 days | 9 L | 5 bottles = 10 L | 3 breakfasts + 6 main portions |
| One adult, 7 days | 21 L | 11 bottles = 22 L; MAFF's example buys two 12 L cases (24 L) | 7 breakfasts + 14 main portions |
| Couple, 7 days | 42 L | 21 bottles = 42 L or four 12 L cases = 48 L | 14 breakfasts + 28 main portions |
| Four people, 7 days | 84 L | 42 bottles = 84 L, or seven 12 L cases | 28 breakfasts + 56 main portions |
These are water and shopping calculations, not minimum calories or a medical diet. One 2 L bottle weighs about 2 kg, and MAFF's one-person 24 L example is heavy. Keep supplies distributed on stable low shelves, without blocking doors, hallways, escape routes or earthquake-safe access. Do not pile a week's water high where it can fall.
First-day rule: put aside three no-heat eating occasions per person before you count food that needs a kettle or a stove. MAFF explicitly describes readily eaten canned food and a first-day no-cook reserve alongside its longer household stock.
Build a Japanese supermarket basket that you will actually eat
For a single adult's first three days, choose:
- 3 easy breakfasts: cereal or sealed bread/crackers, plus long-life milk or an appropriate drink;
- 6 main portions: pull-tab canned fish or beans, safe ready-to-eat retort meals clearly labelled as edible without reheating, or other shelf-stable foods you already like;
- small fruit cups, dried fruit or familiar snacks for variety; disposable utensils and a can opener if needed.
For seven days, keep 7 breakfasts and 14 mains per person, and split them into two groups. Day one has three meals usable when electricity, gas and water all fail. The remaining six days can include dried noodles, rice, instant soups and long-life pouches only if you have separately planned safe water and an authorised way to cook. Dry rice sitting beside an electric rice cooker is not an emergency-ready meal when electricity is gone.
MAFF's example for one adult over a week includes 2 kg of rice, canned proteins, packaged rice, noodles, curry/retort products and snacks; it also mentions a portable stove and cartridges. It is an illustrative mix, not a claim that raw rice can be eaten without heat. If a building forbids a particular stove or ventilation is unsafe, use ready-to-eat food. Never burn charcoal, run generators or use outdoor camp appliances inside an apartment or enclosed balcony.
Where to buy, how to store, and whether you need premium emergency food
A nearby AEON, Seiyu, Life or another Japanese supermarket, a convenience store, a drugstore and household shops such as MUJI can all be places to check for common food or storage products. Availability and prices are shop-specific and not verified here; emergency-labelled foods are optional rather than a required special purchase. Look for clear labels: そのまま食べられる (edible as-is), 常温保存 (room-temperature storage unopened), and 要加熱 (heating required). A product labelled 常温保存 is not necessarily safe for days after opening.
Useful shopping exercise: For one adult, buy five 2 L water bottles plus 3 breakfasts and 6 main portions as a first pass. Later add six more 2 L bottles to exceed 21 L for a week, and enough other meals for 21 eating occasions total. The full seven-day food basket has many possible prices and nutritional profiles; no yen total is claimed without a verifiable dated shelf basket. Spending more on a branded emergency meal does not automatically make it more filling or suitable for your allergies.
The best storage spot is dry, reasonably cool, low and reachable if cupboards are damaged. Split heavy water cartons; don't block the genkan entrance. Keep a mini paper checklist with count and best-before dates. Once a week or with a regular grocery trip, take the next expiring item, eat it, and replace one with one. MAFF calls this simple everyday use-and-replace method rolling stock.
An earthquake stops utilities: what can you eat that night?
Failure case: Your six-day stock is mostly raw rice, cup noodles and refrigerated food. A strong earthquake stops gas, power and water and the fridge warms. On day one, dry rice and noodles are unavailable, and thawed or flood-contacted food may not be safe. The separately reserved pull-tab cans, crackers, unopened shelf-stable drink and drinking water let you eat while you get reliable information and inspect your home.
Check your municipality's hazard map, building safety instructions and evacuation information. If the structure is damaged or an official evacuation is issued, leave. A full pantry cannot make an unsafe apartment safe. You may carry compact food and a manageable bottle, while heavier household water stays at home. Your evacuation bag needs additional identification, medicines, hygiene and communication supplies, not the entire 84 L family reserve.
For infants, older adults, pets, food allergies, swallowing difficulties and chronic illnesses, MAFF recommends preparing specific appropriate foods. Formula preparation, electricity-dependent medical devices and prescription storage cannot be solved by simply dividing an adult food count.
The next grocery trip is enough to begin
Count the people, calculate 3 L × people × days for drinking plus food preparation, and record a first-day no-cook menu. Then aim for three days now and a week as space and budget permit. Keep food rotating normally instead of forgetting an expensive emergency box, and review the municipal hazard map before relying on the apartment for any duration.