Digimon World 1 Evolution Guide: PS1 Rules and Hours (2026)

How does natural evolution work in Digimon World 1?

This Digimon World 1 evolution guide summarizes 1999 PS1 natural digivolution from third-party references—not Definitive Edition numbers. On File Island, your partner digivolves when raising conditions align—not on a fixed story schedule. You need three of four condition groups plus enough in-game age since the last evolution: 6 / 24 / 72 / 144 hours by stage, weight within ±5 g of the target, and mistake bounds tracked in the care mistakes guide.

The four groups (names from community guides):

1. Stats — listed attributes must meet or exceed thresholds.
2. Weight — partner weight must sit within ±5 g of the target’s listed weight.
3. Care mistakes — your mistake count must fall between that form’s minimum and maximum allowed mistakes.
4. Bonus — the fourth condition group named in community guides; specifics vary by species and are not summarized on this wiki.

This structure explains why two players with the same Rookie can diverge: they may hit three different group combinations.

What are the minimum in-game hours between stages?

Evolution timers use in-game hours (clock on your UI), not real-world time. Documented thresholds from the GameFAQs Evolution Requirements guide:

Meeting stat/weight/mistake groups without enough hours typically stalls evolution until the clock catches up—plan training and care around the wait.

How do weight and care mistakes interact?

Weight is a hard window: if you feed or train outside the ±5 g band for your target, that Weight group fails even if stats look perfect.

Care mistakes are counted events (see care mistakes guide). Each evolution defines:

• A minimum mistakes value (some paths need you to have slipped up enough), and
• A maximum cap (too many mistakes block the form).

Critically, care mistake counters reset after each successful evolution. You are judged fresh at In-Training, Rookie, Champion, and Ultimate tiers—not on lifetime mistakes.

Does Definitive Edition change any of this?

The 2026-10-23 trailer shows a 118-slot Digimon chart with a Mega section and new species such as MetalGarurumon and WarGreymon (new Digimon shown). That implies new paths and tiers not present on the US PS1 disc.

The trailer does not list PS1 stat numbers, weights, or mistake ranges for those species. Until the project publishes mechanics:

• Use this page for PS1 nostalgia runs (disc, Recompiled, Maeson).
• Use feature switches to understand which layers are optional in the remake.
• Watch project status for post-release patch notes.

Why is there no full evolution chart here?

A complete species graph requires either datamined tables or exhaustive community spreadsheets. We cite mechanic summaries from named third-party guides, not every branch listing. We do not invent missing paths.

If you need a chart, use established fan databases while remembering Definitive Edition may add slots when New Digimon switches are enabled.

How does evolution relate to saving and care?

Evolution checks run continuously while you raise your partner. Saving in the original game happens only through sleep (ZZZ bubble)—see care mistakes and saving. Poor care can push mistake counts into forbidden ranges before hours accumulate.

For remake context versus other projects, see fan remakes compared.

Worked example (structure only, no species stats)

Pick any Ultimate on a community chart. You will see four groups listed—Stats, Weight, Care Mistakes, Bonus—each with pass/fail criteria. Count how many groups you currently satisfy. If the count is below three, evolution will not trigger even when the on-screen age clock looks high. If the count is three or more, check the hour table (up to 144 in-game hours from Champion) before expecting the cutscene.

Definitive Edition may add Mega targets with unknown groups; the trailer only shows chart slots, not numbers—do not import PS1 thresholds onto new species.

Original vs Definitive Edition — quick reference

Sources & verification

Original-game mechanics: GameFAQs Evolution Requirements guide; background from Wikipedia (JP/EN release dates) and Neoseeker as listed in the PS1 reference sources named below. Definitive Edition cross-check: English trailer (2026-10-23) https://www.youtube.com/watch?v=MfRXYzcOUkQ. Last checked 2026-10-25.