Digivolution and Sources: What Is Under a Digimon

By CardSpicy Founder · October 6, 2026

Quick answer

CardSpicy reads a Digimon card’s printed fields rather than its board position, and digivolution builds a creature by placing cards on top of it — the cards underneath stay part of what it is.

A deck in the Digimon Card Game does not usually deploy its largest bodies straight from hand. It builds them. The mechanic that does the building is digivolution, and it leaves a record: the cards you used are still part of the creature they became.

Digivolving is placing a card on top

To digivolve, you take a Digimon already in play and place another card on top of it, paying the digivolution cost printed on the new card rather than its play cost. The card you place becomes the top of the stack. What was already there stays underneath, in play, as a source.

The stack counts as one Digimon. The top card supplies the name, level, colour and DP that are in play. The cards beneath are sources, and they are not discarded — they are still part of the object.

Sources are not dead cards

A card can carry an inherited effect, which activates while that card is stacked under another Digimon. Cards you can no longer see are therefore still doing work. This is why two stacks built from the same top card can be worth different amounts: what matters is not only what is on top but what is underneath.

Digivolution conditions

Each card prints what it is allowed to digivolve from — typically a level and a colour. Building a stack is therefore a sequence of legal steps rather than a free choice, and the order in which you build it decides which inherited effects you end up holding.

Digivolving is not the same as playing

The official glossary keeps two timings apart. The On Play timing triggers when a Digimon is played directly to the battle area, and the glossary states plainly that it does not apply to a Digimon that digivolved or to one moved into play from the breeding area. The When Digivolving timing triggers when a Digimon on the battle area digivolves. A card that rewards being played does nothing for a stack, and a card that rewards digivolving does nothing for a card played from hand.

Digivolving also carries a digivolution bonus that draws you a card, and a Digimon that digivolves in the breeding area does not activate its When Digivolving effects. The Digimon card index sets out which zones the game uses.

Why the trash is a resource

Because digivolution needs material, the trash is less a graveyard than a second supply of it. One of the game’s seven colours is built around that idea directly: purple works from the trash rather than from the hand, which is the clearest illustration of why the card you discarded is not necessarily gone.

What this page does not claim

No prices, and no card counts. The rules described here are quoted from Bandai’s own glossary, and where the publisher does not define something this page says nothing about it.

Frequently asked questions

What is a source in the Digimon Card Game?

A source is a card sitting underneath a Digimon that digivolved onto it. The sources stay stacked beneath the top card and are part of the same Digimon. Effects can reference them, and a card with an inherited effect can still activate while it is one.

Do On Play effects trigger when a Digimon digivolves?

No. The glossary’s On Play timing applies to Digimon played directly to the battle area and states that it does not apply to digivolving Digimon or to Digimon moved into play from the breeding area. Digivolving has its own timing.

Do you draw a card when you digivolve?

Yes. Digivolving carries a digivolution bonus that draws you a card, and the glossary refers to it when describing the order in which effects resolve.

Can you digivolve a Digimon in the breeding area?

Yes, and the glossary notes that a Digimon which digivolves in the breeding area does not activate its When Digivolving effects. A Digimon in the breeding area also cannot activate effects or be targeted by them.

Why does a card under a Digimon still matter?

Because cards can carry inherited effects that activate while they are stacked under another Digimon. A stack can therefore be worth considerably more than the sum of the costs you paid to build it.

Sources

Rules wording is quoted from Bandai’s own rules and glossary at the date cited and is subject to change. This page is rules and identification, not valuation: we publish no price for Digimon cards, because we have not yet run a checked pull of graded sales for the game.

Related reading

• The Digimon card index — colours, card types and the rarity ladder
• The memory gauge: how a turn ends
• Reading a Digimon card: codes, numbers and rarity marks

Where to go next

• The CardSpicy card index — every card we track, with its PSA 10 population and market history (195 cards).
• The illustrator index — every artist behind those cards, card by card (110 artists).