Watch Brazilian Jiu-Jitsu techniques from any angle and follow each guide step by step. See what comes next, what to try when your opponent blocks it, and keep a log of what you drilled and rolled.
Kurobi’s full-screen 3D viewer playing an armbar from mount: the camera turns around the two fighters, Flip sides swaps top and bottom, and the scrub bar steps through the moves from S-mount to the finish.
Keep the details you learned in class.
You see a technique once in class, and by the next session the details are gone. Kurobi keeps them on your phone: watch a technique from any angle, read the key details and common mistakes, and find the notes you left each time you trained it.
Step by Step
Every technique, from setup to finish.
Each technique has a written guide: the setup, the move and the finish, then the key details and the common mistakes. Most also have selected instructional videos that play right on the page.
Watch it in 3D while you read. Turn the camera, flip to the other side, or go one move at a time.
The armbar from mount in Kurobi: the 3D player above its guide, which scrolls from How to do it through the move and the finish to the key details, the common mistakes and the instructional videos.
What’s Next
Know what comes next, and what to try if they block it.
Guides link to the techniques that start where this one ends, and to the ones to try when your opponent shuts it down. Tap one and keep going.
The spiderweb entry from mount in Kurobi: its What’s next and If they block it rows of animated technique cards, a swipe through them, and a tap that opens the armbar from spiderweb.
Explore
Find any technique by any name.
Browse by goal: submissions, back takes, control, passes, escapes, sweeps and takedowns. Or search by the name your coach uses, in English, Spanish or Portuguese. “Juji gatame” finds the armbar.
Save techniques to collections to look over before class.
Kurobi’s Explore tab: a tap on the Escape goal jumps the list of animated technique cards, then typing “juji gatame” in search finds the armbar from mount and opens it.
Training Log
Log what you drilled, rolled and competed.
Pick the techniques you worked on, top or bottom, and add a note to each. Set how long you trained and how it felt, and for a competition, where you placed.
The next time you open a technique, your notes from earlier sessions are right there.
Logging a drill in Kurobi: Log technique on the armbar from mount opens a new log, 15 minutes is picked, How it felt is dragged up, a note is typed on the armbar, and Done saves the log.
Your Game
See the shape of your game.
Kurobi spreads what you log across eight goals, from submissions to takedowns, with rolling next to drilling, so the thin spots stand out.
Open any technique to see how often you logged it, on which side, and when. Techniques you haven’t logged in 30 days show up as gone cold.
Kurobi’s Analysis tab: an eight-goal web of rolled and drilled techniques unfolds with a count under each goal, the list of logged techniques and Gone cold scroll by, and the armbar from mount opens on its own history.
The Crate
Not sure what to drill? Let Kurobi pick.
Open the crate and it deals you one technique: one you logged lately, one going rusty, one gone cold, or one you’ve never logged. Tap Drill to start a log with it.
Kurobi’s crate: three taps slam the crate open and a card flips over with the dealt technique, a kimura from closed guard last logged 38 days ago, playing in 3D above Drill and Deal another.
Learn. Drill. Log. Repeat.
1
Study the technique.
Watch it in 3D and read the guide before class.
2
Take it to the mats.
Drill it with a partner, then try it in your rolls.
3
Log what happened.
Note what you drilled and rolled, and see where your game is thin.
Kurobi at a glance
What it is
A Brazilian Jiu-Jitsu app with 580+ techniques in 3D, each with a step-by-step guide, and a training journal that tracks the techniques you drilled, rolled and competed.
Platform
iPhone, on the App Store (iOS 16.4 or later). Android, on Google Play.
Price
Free to download. Using Kurobi after onboarding requires Kurobi Pro, a monthly or yearly subscription through the App Store or Google Play. Eligible new subscribers can start with a 14-day free trial.
Technique library
580+ gi and no-gi techniques in 3D, grouped by goal. Each has a written guide, and most also have selected instructional videos.
What you log
Drills, rolls and competitions: the techniques you worked on and on which side, a note on each, time or reps, how it felt, a voice note, and a competition’s name and place.
Offline
The technique library and your logs work offline. Logs sync when you reconnect. Instructional videos need an internet connection.
Languages
English, Spanish and Portuguese.
Who it’s for
BJJ students of any belt level, aged 13 and over.
Account
Sign in with Apple on iOS or Google on Android.
Developer
Mark Isayan
Updated
Questions before you start
A journal only holds what you wrote. In Kurobi each log lists techniques from a 3D library, so you can replay a technique, read your earlier notes on it, and see which goals you drill and roll the least.
Yes. Look up the techniques you learn in class, watch them in 3D, and read the key details and common mistakes. Log them after training so you remember what to ask your coach about.
Your game view shows which of eight goals you train least, and Gone cold lists the techniques you haven’t logged in 30 days. Each guide points to what comes next and what to try if they block it. Or open the crate and let Kurobi pick one for you.
Log each session soon after training, while it’s fresh: the techniques you drilled or rolled, top or bottom, and a short note on each, like the detail that made it work. Kurobi keeps each note with its technique, so the next time you study it, your notes are there.
No app can. Kurobi’s library is a curated reference of 580+ techniques, and names, details and variations differ between instructors, academies and rulesets. The 3D fighters are simplified figures. Use Kurobi alongside your coach’s instruction, not instead of it.
Yes. Log each roll or drill with the techniques you used, top or bottom, and a note. Every technique keeps its own history: how many times you logged it, how often you drilled, rolled or competed it, on which side, and when you last did. Your game view shows which of eight goals you roll least.
Yes. The library covers gi and no-gi grappling, from chokes and armbars to leg locks, guard passes and escapes.
Yes. The technique library and your training log work offline, and your logs sync when you reconnect. Instructional videos need an internet connection.
Kurobi is free to download. After onboarding it needs a Kurobi Pro subscription, monthly or yearly, bought through the App Store or Google Play. Eligible new subscribers can start with a 14-day free trial, and you can manage or cancel the subscription in your Apple Account or Google Play subscription settings.
Kurobi is on the App Store for iPhone (iOS 16.4 or later) and on Google Play for Android.
Yes. Kurobi is available for Android on Google Play.
Give your next round a clear focus.
Learn the technique. Drill it. Log it. Then pick what to work on next.