one dataset · paper, tables, graph, wiki
simgrammar the grammar of simulation

parts

8 mechanics, as Seaman does them

core · 4

biology & health

Creature care

The player sets tank heat, cleans dirty water, and supplies food, and later runs a sprinkler to keep Frogmen moist.

population & lineage

Lifecycle and aging

Mushroomer, Gillman, Podfish, Tadman, and Frogman stages; Podfish parents die after mating and the aquarium becomes a terrarium.

social relations

Natural-language interaction

Microphone speech is matched against the creature's current vocabulary; it asks for the player's birthday and other details and answers in conversation.

time & pacing

Real-time clock

Time follows the real calendar; going much longer than a day without a check can kill the creature.

supporting · 4

agents & behavior

Creature learning

Vocabulary grows through conversation, and the creature becomes tamer over time.

environment & ecology

Habitat suitability

Tank temperature and water cleanliness must suit the current life stage.

agents & behavior

Memories and thoughts

It remembers facts the player shares, such as a birthday, and later tells historical events from that date.

risk & failure

Permadeath

A neglected creature dies permanently.

core loop

check the tank each real day -> adjust heat, clean water, and feed -> talk to Seaman through the microphone -> it learns words and asks about the player -> the life stage advances through breeding and die-off -> raise the Frogman generation and release it

design notes

Yoot Saito built Seaman around speech: a microphone accessory lets the player answer questions and make small talk, early Gillmen repeat the player's words back as gibberish, and the creature's vocabulary grows while it keeps insulting the player. The care loop is sparse but strict, with roughly one check per real day needed to keep it alive, so the game paces itself to the player's calendar. Its life cycle is scripted and harsh: Gillmen fight until two remain, Podfish die after mating, Tadmen eat each other until two remain, and the final Frogmen are released into the wild. Leonard Nimoy narrates the English version as a guide who explains only part of the rules.

appears in

the paper, 2 sections · 1 chapter
paper

5. The structure of the design space

linked in this section of the paper

paper
paper

Appendix A. Game catalog

linked in this section of the paper

paper
catalog

The catalog

listed with its year, developer, subgenre, and number of mechanics

book
ch 2

Chapter 2. Six layers

linked from the text

book

sources

1
Wikipedia contributors (2026). Seaman (video game). Wikipedia

provenance

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