BASIC — Hook: should you make this switch?
The opponent has Stealth Rock up, and you want to pull your weakened Fire-type out to breathe. Before you do, one number has to clear your head: when it comes back in, the rocks chip it again — does it survive that?
You make this exact read a dozen times a game in singles. Players who can run the number switch for free. Players who can't lose a Pokémon the instant it lands on its third trip in — opponent didn't even move, and a mon is gone. This lesson teaches you to run that number.
BASIC — Core: rock damage is a fixed fraction, not a roll
Stealth Rock doesn't roll. It reads off a table. It chips a fixed fraction of your max HP based on your type effectiveness against Rock:
- Neutral (×1): 1/8 (12.5%)
- Doubly resisted (×0.25, e.g. Fighting/Steel): 1/32
- Weak (×2, e.g. Fire, Ice, Bug, Flying): 1/4 (25%)
- Double-weak (×4, e.g. Fire/Flying): 1/2 (50%)
Burn that table in. A Fire/Flying mon loses half its HP every time it lands — it literally cannot pivot into rocks. That's not a strategy problem, it's arithmetic. Spikes only hits grounded non-Flying mons: 1 layer 1/8, 2 layers 1/6, 3 layers 1/4 — and Flying-types and Levitate are immune.
INTERMEDIATE — Worked → Faded
Walk it with me. Your Volcarona (Fire/Bug, double-weak to Rock) has max HP = 175. Opponent's Stealth Rock is up.
- First landing: 175 × 1/2 = 87 damage, leaving 88.
- You pivot out, recover a little, pivot back: another 87, leaving 1.
- Third landing: straight to 0.
So with rocks up, Volcarona gets exactly two safe entries — the third is a free kill for the opponent. That's why Fire/Bug and Fire/Flying mons see their value cut in half the moment you can't clear rocks.
Your turn. Your Corviknight (Steel/Flying) is neutral to Rock — Steel resists Rock (×0.5) and Flying is weak to Rock (×2), which multiply to ×1. Max HP = 202. Rocks are up. How much chip per landing, and how many times can it land before chip alone kills it (no recovery)?
(Run it yourself first… Answer: neutral = 1/8, so 202 × 1/8 = 25 per landing; 202 ÷ 25 ≈ 8, so it can land eight times safely before the ninth entry would kill it from chip. Takeaway: Corviknight pivots in and out almost completely freely under rocks — which is exactly why it's so often the Defog user. It barely fears its own job.)
INTERMEDIATE — When / which move (if-X-then-Y)
You hold two clearing tools, each with a blind spot:
- Rapid Spin: clears hazards on your side only, plus a small Normal hit (50 BP). But it's Normal-type — if the opponent has a Ghost, they switch it in, the spin whiffs, and your rocks sit there untouched.
- Defog: clears hazards on both sides plus screens, never blocked by Ghosts. The cost: your own rocks and Spikes go with it.
The decision chain:
- If your core includes a Fire/Ice/Flying mon that fears rocks → you must carry removal. Running a rock-weak attacker with no way to clear is a structural hole.
- If the opponent has a Ghost → don't bank on Rapid Spin. Either run a Defog user instead, or bait the Ghost out first before you spin.
- If you're stacking your own Spikes to grind them down → know that both clearing moves wipe your own side too. There's no clean way in singles to keep your hazards while removing theirs — you keep yours up by pressuring switches so hard the opponent never gets a free turn to clear.
INTERMEDIATE/ADVANCED — Exceptions where the simple rule breaks
- Heavy-Duty Boots: a mon holding Boots is completely immune to all entry hazards. If the opponent's Fire/Flying is on Boots, your rocks do nothing to it — the whole "two entries" math above is void. When an enemy core walks through rocks untouched, suspect Boots first.
- Magic Guard: immune to all indirect damage, hazards included. Clefable just ignores the hazard war.
- Flying/Levitate vs. rocks: Levitate and Flying dodge Spikes, but they do not dodge Stealth Rock — rocks are typed, not grounded. People constantly conflate the two.
- Mega Evolution typing shifts: Mega Evolving can change a mon's typing, which changes its Rock multiplier. Always compute the chip off the typing it has at the moment it lands.
INTERMEDIATE/ADVANCED — Mistake autopsy
The classic beginner error: Defog-ing away the opponent's rocks before you've set your own. Result — the opponent just re-sets rocks next turn (it's a one-turn move), you've kept nothing of your own, you've blown a turn of tempo, and you may have cleared Spikes they'd stacked, doing their cleanup for them.
The fix: clearing is a reaction, not a free opening move. Confirm there's actually a hazard hurting a key Pokémon before you remove it. Go one level deeper: before clearing, ask "how many turns does it cost them to re-set? Rocks take 1 turn — so is the value of this clear only worth one mon's worth of HP?" The value of a clear = HP you save this turn ÷ the opponent's cost to re-set.
INTERMEDIATE — Predict, then reveal
Q: The opponent has a Gholdengo (Ghost/Steel) on their team, and your only removal is one mon with Rapid Spin. Their Stealth Rock is up, grinding your Fire-type core. What do you do this turn?
Think for 10 seconds before reading on.
A: Don't just spin. Gholdengo is a Ghost — they'll switch it in to block your Rapid Spin (Normal doesn't touch Ghost), the rocks stay, and you've burned a turn. The right line is to force out or remove Gholdengo first (threaten it with a check, or predict its switch-in), then spin once the spin-blocker is off the field. Or reframe entirely: instead of clearing over and over, put Heavy-Duty Boots on that Fire core so rocks never touch it again — a permanent fix instead of a turn-by-turn tax.
ADVANCED — Now do this (in the Dex)
Open the Dex ( is already wired up) and do three things, against your own six:
- Compute each mon's Rock multiplier. Run every member's typing and mark the fraction it takes per landing. Flag the double-weak ones (Fire/Flying, Fire/Bug, Ice/Flying) red — those are your "rocks must be cleared or Booted" cards.
- Count your removal blind spots. Do you carry a Rapid Spin or Defog user? The enemy team will likely have a Ghost — will your Rapid Spin get blocked? Missing both is the next slot to fix.
- Boot the most rock-fearful mon. Run the math: with Heavy-Duty Boots, its landing damage goes to zero — do you even still need a dedicated remover slot for it? Often one item saves you a whole team slot a clearer would have cost.
Do those three and your "should I switch?" read stops being a guess and becomes a calculation.