Yu-Gi-Oh custom card simulator
The duel simulator that understands your custom cards
People have asked for years where they can play Yu-Gi-Oh with custom cards without doing the rules by hand. YGOWB is the answer: a full duel simulator where custom cards are first class, and the engine enforces every effect for you.
Automatic rules, even for cards that did not exist yesterday
There have always been two kinds of Yu-Gi-Oh simulator. Manual simulators let you upload any card image, but you move the cards yourself and both players have to agree on what each effect does. Automatic simulators enforce the rules, but adding a new card means writing a script in a programming language.
YGOWB closes that gap. Card effects are built from structured blocks in the Card Studio, and the duel engine reads those blocks directly. So a card you invented ten minutes ago gets the same treatment as a classic: legal move checks, Chains, targeting, costs, phases and damage calculation, all handled for you.
If you have been using Duelingbook's custom cards, or writing EDOPro scripts, and what you really want is automatic rules without programming, YGOWB is built for exactly that.
| Manual simulators | Scripted automatic simulators | YGOWB | |
|---|---|---|---|
| Custom cards | Yes, as images | Yes, if you write a script | Yes, built from blocks |
| Rules enforced | By the players | By the engine | By the engine |
| Skill needed to add a card | None | Programming | None |
| AI opponent for custom cards | No | Depends on the script | Yes |
| Install | Usually none | Usually a download | None, runs in the browser |
What the simulator handles for you
Legal moves only
Summons, Sets, Tributes, attacks and activations are offered only when the rules allow them.
Chains and responses
Traps and Quick effects get their response windows, Chains build and resolve in the right order.
Fusion and Ritual Summons
Materials, Ritual Spells and the Fusion Deck all work, with a proper summoning ceremony on screen.
Hidden information stays hidden
Online duels run on the server. Your opponent's browser never receives your hand or your face-down cards.
Banlist per World
Each World owns its Forbidden and Limited list, and decks are validated against it before a match.
Replays and spectating
Finished duels can be watched back move by move, and Worlds can allow live spectators.
Three ways to play
Online match. Best of three against another player, with a match clock, rock paper scissors for the first turn and reconnect support. See playing custom cards online.
Practice vs AI. A computer opponent that plays any deck from your World, custom cards included. See playing against the AI.
Hot-seat duel. Two players, one screen. Good for testing a new card with a friend on the couch.
Questions
Is YGOWB an automatic or a manual simulator?
Automatic. The engine knows every card's effect, so it offers only legal moves, builds Chains, asks for targets and costs, and applies the result. You never drag cards around and resolve effects on trust.
How can an automatic simulator support custom cards?
Custom card effects are built from structured blocks in the Card Studio instead of free text. The same engine that runs the classic cards reads those blocks, so a brand new card plays by the rules the moment it is published.
Which Yu-Gi-Oh rules does the simulator use?
The classic rules up to 2005: five Monster Zones, Fusion and Ritual Summons, Tribute Summons, no Synchro, Xyz, Pendulum or Link. Each World also has its own Forbidden and Limited list.
Do I have to install anything?
No. YGOWB runs in the browser on desktop and on phones. A native desktop client is in development.
Can I play with real classic cards too?
Yes. Public classic Worlds cover more than 1,800 cards released between 2000 and 2005, ready to join and play. They run on the same engine as your custom cards.
Stop resolving effects by hand
Make the card, build the deck and let the simulator run the duel.