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simgrammar the grammar of simulation

core loop

pet calls for attention -> feed a meal or snack, play, scold, clean, or give medicine -> meters and care history accumulate -> pet ages after each sleep -> care history selects its next form -> it lives on or dies

design notes

Aki Maita and Akihiro Yokoi reduced a pet to three meters (Hunger, Happy, Training) plus droppings and sickness on a three-button LCD device that runs continuously; early units could pause only through the clock settings. Meals fill Hunger, snacks and a minigame raise Happy but excess snacks cause illness, scolding when the pet calls for attention fills Training, and uncleaned droppings lead to sickness shown by a skull. Each life stage lasts a set number of days and age advances when the pet wakes, and care quality selects the adult character, turning care history into a visible outcome (proposed as care-dependent-development).

relations

8 stored edges
uses

Creature care

Care actions are meal, snack, game, scold, clean, and medicine; meals are limited by fullness while snacks are not, and excess snacks cause sickness.

core
uses

Lifecycle and aging

Baby, Child, Teenager, Adult, and Special stages (plus Senior in some models) each last a set number of days, with age advancing on waking; old age eventually ends its life.

core
uses

Needs decay

Hunger and Happy meters, shown as hearts, deplete over real time and are refilled by meals, snacks, and the minigame.

core
uses

Real-time clock

The pet lives on the device clock set at hatching and sleeps nightly; time keeps passing between check-ins.

core
uses

Alerts feed

The device beeps and shows an attention icon when the pet needs care or calls for discipline.

supporting
uses

Care-dependent development

Care quality during each life stage, such as unanswered calls, overfeeding snacks, and uncleaned droppings, selects the next form, so the same egg can grow into different adult characters.

supporting
uses

Day-night cycle

A nightly sleep period suspends care demands and marks age increments.

supporting
uses

Permadeath

Poor care, sickness, or old age kills the pet; the A and C buttons start a new egg.

supporting

backlinks

computed from other records

sources

1
Wikipedia contributors (2026). Tamagotchi. Wikipedia

provenance

runs in log/runs
2026-10-24
created2026-10-24-catalog-gccatalog