Underhook: BJJ & Jiu Jitsu

You train two or three times a week. The questions pile up faster than that: why did that sweep work, why do you keep getting caught in the same choke, what were you supposed to do from half guard? Underhook turns those questions into a 5-minute daily habit.

Underhook is a decision trainer for Brazilian Jiu-Jitsu, built the way the best learning apps are built: a structured path, short daily sessions, a streak worth protecting, and a rival who plays for real. Every question drops you into a real position and asks the only thing that matters on the mat: what do you do next?

THE PATH
• A guided path from day-one white belt to blue belt: survival, escapes, guard, passing, sweeps, submissions, and the strategy that connects them
• 1,000+ scenario questions built on 10 core mental models, so you learn principles you can apply from any position, not moves to memorize
• Lessons, quizzes, coach chats, podcast debates and voice lessons: 11 formats keep every session fresh
• Stripe tests along the way, one belt test at the summit. The path ends at blue belt. We mean it.

THE GYM
• Quick Roll: fast sparring quizzes against a gym roster of 12 rivals, from day-one rookie to black belt
• Kat, your AI rival: she plays to win, remembers exactly where your game broke last time, and targets that hole in the next fight (Pro)
• Stamina, streaks, XP and stripes keep the habit honest
• Fully available in English, Portuguese, Spanish and Ukrainian

BUILT FOR REAL TRAINING
Underhook is a supplement, not a substitute. It will not replace mat time and it will not promise you a belt. What it does is make your mat hours stick: 5 minutes a day so the questions you train on the mat actually make sense in class.

Made for adult hobbyists: new white belts drowning in information, blue belts stuck on a plateau, busy people who can't add a fourth class, and anyone sidelined by an injury who refuses to lose their game.

FREE AND PRO
The whole path is free: every lesson, every position, all the way to the belt test. Every new account also starts with 3 days of Underhook Pro, free, with no card and no auto-charge. Pro removes daily limits with unlimited stamina, unlocks Kat the Rival, and adds a second streak freeze. Monthly and annual plans and a one-time lifetime option are available in the app; prices are shown before you pay.

Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. Payment is charged to your Apple Account at confirmation of purchase. Manage or cancel anytime in your Apple Account settings.

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Privacy Policy: https://underhook.xyz/privacy

See you on the mats. Oss.