Pokemon Stadium Cup Rules, and a Prime Cup You Can Play

Pokemon Stadium, the Nintendo 64 one, has been on Nintendo Switch Online since April 12, 2023, and that version cannot connect to the Game Boy games. So everybody playing it on Switch is playing with rental Pokemon, and everybody meets the same rules screen. Four cups, four level ranges, a level limit that only counts three of your six, a height and weight check in one of them, and three clauses that quietly decide how battles end. Here is the whole rulebook in one place, and below it the Prime Cup running in my own Gen 1 battle engine, with the real rentals and the real trainer teams.

Now I know what you're thinking: how do I know these rules are right? Every rule here comes from sources I actually read (Bulbapedia, Serebii, a data rip of the game itself, and the Stadium code in Pokemon Showdown), most of them confirmed by two or more, and where they disagree I say so instead of quietly picking one. Already know the rules? Skip straight to the playable Prime Cup, no hard feelings!

The four cups Shared rules Petit Cup's 45 Play the Prime Cup What Stadium changed Where the data comes from

What are the four Stadium cups?

Stadium mode has four cups, and each one is its own little format. The levels apply to every Pokemon you enter, but the level sum only counts the three you actually bring into a battle, which is the part that confuses people the most.

What rules do all four cups share?

Some rules never change from cup to cup, and these are the ones that catch people out, so here they are in the order they tend to bite.

1. Register six, bring three. You enter six Pokemon and choose three of them for each battle. All six have to be different species, which is the Species Clause. (Rentals are one per species, so on Switch this one takes care of itself.)
2. Team preview. Before you pick your three, you see the other trainer's six, and they see yours. The surprise Gengar in the back is not a surprise anymore.
3. Sleep Clause, Stadium style. You cannot put one of their Pokemon to sleep while another of theirs is already asleep. Here is the twist: a Pokemon that put itself to sleep with Rest counts too, so a resting Chansey blocks every sleep move you have until it wakes up. Rest itself is never blocked.
4. Freeze Clause. You cannot freeze one of their Pokemon while another of theirs is frozen. Your Ice Beam still hits, it just won't freeze.
5. Self-KO Clause. If your last Pokemon uses Selfdestruct or Explosion, you lose, even if it takes their last Pokemon down with it. No forcing a tie!
6. No items, no timer. Items can't be used in battle, and Stadium mode has no time limit (the optional timer lives in the Event Battle mode).
7. Eight in a row. A cup, or one division of a cup, is eight trainers back to back. Win a battle without a single faint and you earn a Continue, which lets you retry a trainer after a loss.
8. Rentals have no PP Ups. A rental Blizzard has its plain 5 PP, so spend them like they are precious (because they are).

Wiki rule tables also list an Item Clause and an Event Clause. Held items didn't exist until Gold and Silver, so the Item Clause only matters in Stadium 2, and the Event Clause is simply the Mew ban in the Pika and Poke Cups (Mew was an event-only Pokemon).

What changes in Round 2?

Beat Mewtwo (it shows up once you clear Stadium mode and the Gym Leader Castle) and Round 2 unlocks, toggled with C-Right on the main menu. Same trainers, different Pokemon, much higher difficulty, and the Stadium switches to night. In the Prime Cup, Round 2 also adds Mew to the rental list.

The cups, one by one

Pika Cup: levels 15 to 20

The Pika Cup is the low-level cup, and it only exists in this Stadium (it didn't come back in Stadium 2). Each Pokemon has to be level 15 to 20, and your three can add up to 50 at most, so three level 20s is out (that's 60!) while two level 15s and a level 20 lands exactly on the line. Mew is the only name on the in-game ban list, and Mewtwo is out in practice because nobody can catch it that low (the only Mewtwo in Red and Blue waits in Cerulean Cave at level 70, and levels only go up). One division, eight trainers, 91 rentals.

Petit Cup: levels 25 to 30, and the size check

The Petit Cup is the strangest one, and the one people get stuck on the most. Levels 25 to 30, a level sum of 80 for your three, and then the fun part: only unevolved Pokemon (the lowest stage as of Red and Blue, so Pikachu counts), no taller than 2.0 m (6'07"), no heavier than 20.0 kg (44.1 lb), and no Mew. Only two single-stage Pokemon make the cut, Ditto and Farfetch'd, since everything else that never evolves is too big or too heavy. That leaves exactly 45 eligible Pokemon, and every one of them is a rental:

• Bulbasaur
• Charmander
• Squirtle
• Caterpie
• Weedle
• Pidgey
• Rattata
• Spearow
• Ekans
• Pikachu
• Sandshrew
• Nidoran♀
• Nidoran♂
• Clefairy
• Vulpix
• Jigglypuff
• Zubat
• Oddish
• Paras
• Diglett
• Meowth
• Psyduck
• Growlithe
• Poliwag
• Abra
• Machop
• Bellsprout
• Geodude
• Magnemite
• Farfetch'd
• Shellder
• Gastly
• Krabby
• Voltorb
• Exeggcute
• Cubone
• Koffing
• Horsea
• Goldeen
• Magikarp
• Ditto
• Eevee
• Omanyte
• Kabuto
• Dratini

Poke Cup: levels 50 to 55

The Poke Cup is the one most people mean when they say Stadium. Levels 50 to 55, a level sum of 155 for your three (one level 55 and two level 50s, say, or 52, 52 and 51), and Mewtwo and Mew are banned. It comes from the Nintendo Cup '97 rules and has four divisions of eight trainers: Poke Ball, Great Ball, Ultra Ball and Master Ball. All 149 of its rentals are level 50. (The Japanese release swapped this cup for three Nintendo Cups, '97, '98 and '99, if you ever wondered why Japanese footage looks different.)

Prime Cup: anything goes, at level 100

The Prime Cup is the big one. Any level from 1 to 100 is allowed, there is no level sum, and nothing is banned, Mewtwo and Mew included. Every CPU trainer brings level 100 Pokemon, though, so anything lower is just a handicap. Four divisions of eight trainers again, and the seventh and eighth battles of each division are the semifinal and the final. The rentals are all level 100: 149 of them in Round 1, and 150 in Round 2 once Mew joins. Mewtwo is never a rental, so a rentals-only player can't bring one.

One thing the rental screen never tells you is that rentals are not fully trained. Every Prime Cup rental has fixed DVs and stat experience baked in, and the pattern is surprisingly tidy. 52 rentals have DVs of 11, 10, 11 and 11 (Attack, Defense, Speed, Special), 37 have 6, 7, 7 and 7, 19 have 2, 2, 3 and 3, two odd ones out (Slowbro and Jynx) have 2, 2, 3 and 1, and 40, including Venusaur, Charizard, Blastoise and Alakazam, have zero across the board. 136 of the 150 carry 25,600 stat experience in every stat (Mew gets just 6,400). That is why a rental Venusaur has 310 HP where a perfectly trained one would have 363. Sorting the rental list below by a stat is the most honest tier list you'll find, since it comes straight from the numbers.

Play the Prime Cup

Here is the fun part! Pick a round and a division, register six rentals, look at the trainer's six, choose your three, and battle. The trainers are the real Prime Cup trainers in their real order, with their real Pokemon, moves and stats, and your rentals are the real rentals down to the DV. What isn't real is the CPU's brain: it picks its three and its moves with a simple rule of thumb I wrote (skip moves that can't work, lean toward big hits), not Stadium's own AI, so please don't use it to predict the N64. The battle itself enforces the Species, Sleep, Freeze and Self-KO Clauses exactly as described above, and it uses the Stadium mechanics marked Yes in the table further down.

What did Stadium change from Red and Blue?

Stadium fixed a pile of Red and Blue's famous bugs and changed some rules on purpose. The table shows each change, what Stadium does, and whether this lab's cup mode does it too. Cup mode is only switched on inside this page, so the free Gen 1 battler keeps its Red and Blue model. Where the sources disagree, I left the engine alone and said so. Never trust a mechanic I didn't actually build!

Cup mode also fixes four things that aren't Stadium changes at all, just Gen 1 rules the free battler doesn't follow yet. Quick Attack moves first (it has +1 priority). Thunder Wave can't paralyze Ground types. Roar, Whirlwind and Teleport do nothing in a trainer battle instead of ending it. And a Substitute soaks up everything that rides along with a hit, so no paralysis, burn, freeze, flinch, confusion or stat drop gets through, not even on the hit that breaks it, while stat-lowering moves like Growl and confusion moves like Supersonic simply fail against it. That last one comes straight from the Red and Blue disassembly, where every one of those effects checks for a Substitute first and a breaking Substitute wipes the attacker's effect, and Showdown's Stadium code agrees.

Sources for the table: the changes list on Bulbapedia's Pokemon Stadium page and its critical hit, Focus Energy, Hyper Beam and stat modifier pages, Smogon's A Beginner's Guide to Pokemon Stadium, and the Stadium battle code in Pokemon Showdown, which gives the crit formula as the exact bit shifts I copied. Every row marked Yes is described the same way by at least two of the three.

Where does the data come from?

The rentals and every Prime Cup trainer team come from SadisticMystic's Pokemon Stadium lookup sheet, a data rip of the game shared by the Stadium speedrunning community, with DVs, stat experience, stats and moves for every Pokemon. I didn't take it on faith, though. My engine already has every species' base stats from the Red ROM, so I recomputed all 534 stat lines (150 rentals and 384 trainer Pokemon) from the Gen 1 stat formula using each one's DVs and stat experience, and all 534 match the sheet exactly.

The moves got a second and third opinion. The rental movesets match Bulbapedia's Prime Cup rental list for 149 of 150 Pokemon, and the odd one out (Squirtle) matches Serebii's rental list, so every rental has at least two sources agreeing. The trainer teams match Bulbapedia's Round 1 and Round 2 lists for 381 of 384 Pokemon. For the last three I checked Serebii and went with the majority: the Round 1 Poke Ball Rocket's Nidoran♀ uses DoubleSlap (the rip says Double Kick), the Round 1 Great Ball Cueball's Charmeleon uses Ember (the rip says Leer), and for the Round 1 Poke Ball Gambler's Nidoran♂ the three sources give three different sets, so it gets the three moves at least two of them share: Horn Drill, Body Slam and BubbleBeam.

The cup rules come from Bulbapedia's Stadium Cup, Pika Cup, Petit Cup, Poke Cup, Prime Cup and Rule variants pages, cross-checked against Serebii's Stadium cup pages. They differ in two places. Serebii rounds the Petit Cup size limit to 6'08" and 44 lb, and this page uses Bulbapedia's metric figures. And Serebii lists every Pokemon as usable in the Pika Cup, while Bulbapedia notes that Mew is on the in-game ban list, so this page goes with the in-game list.

What's missing, and what comes next?

• Playable Pika, Petit and Poke Cups. My engine only runs level 100 battles right now, so those three cups get the rules above but no playable bracket yet. Variable levels are the next thing on the list, and once they land the other cups can reuse everything this page already does.
• Moves the engine doesn't model yet. Wrap, Bind, Fire Spin and Clamp hit once with no trapping, Thrash and Petal Dance hit once with no lock-in, Jump Kick and Hi Jump Kick never crash, Mist shows its message but blocks nothing, Counter is a feeble one-power hit, and Leech Seed, Disable, Bide, Mimic, Mirror Move and Conversion do nothing at all. The rental cards mark every one of them so you can plan around it.
• Stadium's own AI. The CPU here is my rule of thumb. It won't pick Selfdestruct or Explosion with its last Pokemon while it has anything else to use (the Self-KO Clause would hand you the win), and it won't pick a sleep move the Sleep Clause would block, but it isn't the N64's brain. (Metronome can still roll an Explosion, and then the clause applies to that too.)

Alright, go ahead and try the Poke Ball division with a random six, it's a great way to meet rentals you'd never pick on purpose (hello, Metapod). And if you catch a rule I got wrong, or a rental that doesn't match your game, tell me on the contact page and I will fix it. I would really appreciate it!