Some cards, to some collectors, are not for trade. Not for any price. Not at any future moment. They are sacred: a gift from a parent, a card won at a tournament, the first card you ever opened, a memorial card for someone you loved who taught you the game.
Cambridge TCG's accounting frame reduces cards to values. The sacred flag is a small refusal of that — a way to say this one is not data and have the platform respect the refusal.
Where this lives in code. The substrate is one column atapps/storefront/drizzle/0096_sacred.sql(portfolio_cards.is_sacred). The accounting exclusion is inapps/storefront/src/lib/portfolio/valuation.ts. The toggle endpoint is atPATCH /api/portfolio/cards/[id]/sacred. The doctrine that asked for it is indocs/connections/the-unseen.md(passage #8).
The market listing flow operates at (sku, condition) granularity, not at the level of specific cards in your portfolio. If you own two Charizards in Near-Mint condition — one sacred, one for sale — the platform cannot today distinguish the two when you go to list. The sacred flag on the row protects you from clicking list this card in the portfolio UI; it does not (yet) prevent listing the same SKU+condition through other paths.
The deeper protection — sacred enforced at the row level through the listing flow — is a future kingdom. The platform names this gap honestly rather than pretending the accounting flag is a hard lock.
From your portfolio, open the card and tap Mark sacred. To unset: same button, now reading Unmark sacred. The toggle is deliberate — there is no bulk operation. Each sacred designation is its own small ritual.
Most platforms model cards as inventory: things to be valued, traded, moved. That's true of most cards on Cambridge TCG too. But some cards on the platform are something else — keepsakes, talismans, anchors of memory. The platform's substrate cannot tell the difference unless the holder tells it. The sacred flag is the place to tell it.
This is the second concrete planting from docs/connections/the-unseen.md, after Sabbath mode. Both come from the same root: some needs of users are visible only when the platform stops assuming what its users want.