How to test a One Piece TCG deck properly
Most players change their deck after every loss. That is not testing — it is superstition with a card sleeve.
The short version
- Testing has three stages: opening hands, goldfishing without an opponent, and real matchup repetitions.
- Twenty opening hands tell you whether the deck's curve works, and take under ten minutes.
- A single loss is not evidence. Change a card only after seeing the same problem in several games.
- Record why you lost, not that you lost: no early play, no removal, no Counter, flooded on expensive cards.
- Test against the decks you will actually face, in the proportion you will actually face them.
There is a familiar loop: build a deck, lose a game, blame a card, cut it, lose the next game to the absence of that card. Testing is the discipline that breaks the loop, and almost none of it requires an opponent.
Stage one: twenty opening hands
Shuffle, draw five, write down whether the hand is a keep. Put the cards back, repeat twenty times. It takes about eight minutes and it answers the most important question about any deck: does it function on time?
- Below 60% keepable — the curve is broken. You need more cheap cards, not different expensive ones.
- 60–75% — normal. Move on.
- Above 85% — suspiciously smooth. Check that your deck actually does anything powerful, rather than merely something on every turn.
Use the same keep criteria every time so the number means something — the mulligan guide defines a workable standard.
Stage two: goldfishing
Play the deck against no opponent. No blocks, no Counters, no removal. Play out six or seven turns and note what happens.
| What you are measuring | How | What a bad result looks like |
|---|---|---|
| Speed | Which turn could you first threaten lethal, unopposed? | Turn seven or later for a deck you thought was aggressive |
| DON!! usage | How much DON!! goes unspent each turn? | Two or more wasted DON!! on several turns running |
| Dead draws | How many cards sat in hand doing nothing? | The same card is stranded in most games |
| Engine consistency | How often did you see your key card by turn four? | Under half the time, with no way to search for it |
Stage three: real games, recorded
Now you need opponents — a local, a playgroup, or an online client. Playing online is the fastest way to get volume. The rule is simple: play in blocks of ten, change nothing inside a block.
After each game write one line: the opponent's Leader, whether you were first or second, and the single reason the game went the way it did. Something like *lost, on the draw, no play until turn three*. Ten of those lines is a diagnosis. One is an anecdote.
| Recurring note | What to change |
|---|---|
| No early play | Add cheap Characters; cut the highest cost tier |
| Ran out of cards by turn six | Add draw or search effects, or lower the average cost |
| Could not remove their key Character | Add removal, or add a way to attack around it |
| Flooded on expensive cards | Cut one copy of each 6+ cost card before adding anything |
| Lost to one specific Leader repeatedly | That is a matchup problem, not a deck problem — decide whether it is common enough to build against |
Change one card at a time, and only after ten games. Anything faster and you are measuring variance, not decisions.
Testing against the right decks
There is no point beating a deck nobody plays. Find out what is actually winning at the level you play at — regionals results are a different format from your Tuesday local — and weight your practice accordingly. How to read the meta covers where to find that data and how much to trust it.
A week of testing in about three hours
Monday: twenty opening hands
Ten minutes. Fix the curve before anything else.
Tuesday: five goldfish games
Twenty minutes. Establish the deck's fastest realistic clock.
Wednesday and Thursday: ten real games
Change nothing. Write one line per game.
Friday: read your notes
Look for the reason that appears three or more times. That is the only thing worth changing.
Saturday: change one thing and repeat
One card, or one count. Then another ten games before the next change.
Keeping the list itself under control matters too — track which versions you have tried so you do not quietly rebuild a deck you already rejected two weeks ago.
Frequently asked questions
- What is goldfishing in One Piece TCG?
- Playing your deck with no opponent to see how fast and how smoothly it operates. It measures your deck's best case: how quickly it can develop a board and threaten lethal when nothing interferes.
- How many games do I need to test a deck?
- At least ten games per change, and ideally more. Fewer than ten and you are reading variance rather than the effect of the change.
- Should I change a card after losing with it?
- Not on its own. Record why the game was lost and look for a reason that repeats across several games. A single loss almost never contains enough information to justify a change.
- Can I test properly without an opponent?
- Partly. Opening-hand checks and goldfishing need no opponent and answer most curve and consistency questions. Matchup and defensive questions need real games.
- How many opening hands should I draw when testing?
- Twenty is enough to see whether the deck's curve works. If fewer than about twelve of them are hands you would keep, the cost curve needs fixing before anything else.
Sources
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