What it does
Chople Berry only covers Fighting: an opponent lands a super-effective Fighting move on the holder, that hit gets halved, and the berry is eaten.
Fighting is worth covering because it punishes three pillars of every meta — Dark, Steel, and Normal. Close Combat, 120 base power with great coverage, is the standard answer to cores like Kingambit and Tyranitar. Bulky as those mons are, a super-effective Fighting hit often leaves them in the red or just KOs them. Chople halves it, turning "broken through" into "still standing," and you get a turn to hit back.
Compared to Focus Sash, the difference is who runs it. Chople usually goes on tanks like Kingambit and Snorlax that don't need Sash's full-HP safety net — they already have the HP, they just need to not get one-shot by Fighting. Sash needs full HP and dies to chip; Chople works from any HP and patches exactly that one bulky-mon weakness.
Who runs it
The carriers are bulky mons for whom a Fighting weakness is the real problem.
Kingambit (52%!) is the headline user. Dark/Steel, 4× weak to Fighting — one Close Combat basically removes it. And it's a slow setup finisher, so it badly needs to survive that hit to stack Swords Dance or click Kowtow Cleave for the kill. After the halving, its 4× weakness behaves like 2×, which often drags "guaranteed KO" back to "survives."
Maushold (47%), Normal, has Fighting as its one real weakness — Chople lets it eat a hit and keep clicking.
Tyranitar (32%), Rock/Dark and 4× weak, runs it for the same reason as Kingambit. Incineroar (23%), Fire/Dark, uses it to stick around for another Intimidate. Snorlax (10%), Kangaskhan (5%) — Normal types — plus Hydreigon (6%) and Archaludon (7%) all carry a Fighting weakness too.
How to use it
The rule: hold it for that one Fighting hit.
With your berry-holding Dark or Steel out and a Fighting attacker across from you lining up Close Combat or Drain Punch, eat the halved hit, stay up, keep the turn. For Kingambit, surviving that hit usually means a Sucker Punch the next turn for the revenge KO.
Close Combat has a built-in catch for the attacker: it drops the user's Defense and Sp. Def a stage each. After you tank the halved hit, that mon's defenses are now broken, so your swing back hits harder — Chople doesn't just save you, it opens the revenge window.
It only triggers once. A mon like Maushold that wants multi-turn damage still eats full price on the next Fighting move after the berry pops, so don't treat it as an infinite shield.
Tips & strategy
The big scenario is Kingambit against Fighting. The opponent clearly wants to KO your 4×-weak Dark/Steel with Close Combat and has the damage worked out — then Chople halves it, you live, and you Sucker Punch for the kill next turn. That swing is exactly why Chople sits at 52% usage on Kingambit.
Don't give it to anything Fighting doesn't hit super-effectively. Chople only halves when Fighting is super-effective; neutral or resisted, it does almost nothing.
Run the number first. A 4×-weak mon at half damage is roughly 2×-weak, which is often just enough to live — but if the Fighting attacker overkills hard, the halving won't save you. Then skip it and run an attacking item instead.