Obo | One By One
Master Japanese, One by One.
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
Study smarter with Obo — spaced-repetition flashcards, kana foundations, and kanji lookup built for learning Japanese every day.
Master Japanese with ObO - Your Personal Language Learning Companion
ObO makes learning Japanese simple, effective, and enjoyable. Whether you're preparing for JLPT, planning a trip to Japan, or just starting your language journey, ObO adapts to your learning style.
KEY FEATURES:
• Smart Spaced Repetition (FSRS v5)
- Learn efficiently with scientifically-proven algorithms
- Cards appear exactly when you need to review them
- Track your progress with detailed analytics
• AI-Powered Smart Add
- Generate flashcards instantly with AI
- Enter words or describe topics in your own language
- Save time creating study materials
• Perfect for Beginners
- Step-by-step Hiragana & Katakana guide
- Interactive kana practice with immediate feedback
- Beginner-friendly onboarding walks you through everything
• Flexible Study Options
- Ready-made template decks (JLPT N5-N1)
- Import your Anki decks
- Create custom decks for any topic
- Grammar, vocabulary, kanji - all in one place
• Beautiful & Intuitive
- Clean, distraction-free interface
- Dark mode support
- Smooth animations
- Designed for daily study habits
• Premium Features
- AI Smart Add with generous free quota
- Premium decks curated by experts
- Priority support
- Unlock unlimited potential
LEARNING PATHS:
For JLPT Students:
Complete decks from N5 to N1 with thousands of essential words and grammar points.
For Travelers:
Quick study packs with practical phrases for dining, transportation, shopping, and emergencies.
For Anime/Manga Fans:
Learn the Japanese you hear in your favorite shows and read manga in the original language.
For Serious Learners:
Advanced customization, grammar analysis, and comprehensive study tracking.
WHY OBO?
• Offline-first: Study anywhere, anytime
• No ads interrupting your learning
• Privacy-focused: Your data stays yours
• Regular updates with new features
• Responsive support team
Start your Japanese learning journey with ObO today. Whether you're studying 10 minutes a day or several hours, ObO helps you make consistent progress toward fluency.
Download now and get started for free!
more • Announcements now appear only after you’re signed in and finished onboarding
• Offline Indonesian meanings for kanji lookup
• Paid deck titles update correctly when you switch language
• Bug fixes and polish for a smoother study experience
1.6.9 Jul 31
Look up Japanese words anywhere.
• Share Japanese text from any app to Obo and instantly look up words (Yomitan-style), powered by an offline JMdict dictionary.
• Indonesian meanings — see definitions in Bahasa Indonesia, not just English.
• Save with AI — tap to add a word to any deck and Obo's AI builds a complete flashcard: reading, meaning, and a natural example sentence (1 coin).
Plus stability and performance improvements.
1.6.8 Jul 7
Look up Japanese words anywhere.
• Share Japanese text from any app to Obo and instantly look up words (Yomitan-style), powered by an offline JMdict dictionary.
• Indonesian meanings — see definitions in Bahasa Indonesia, not just English.
• Save with AI — tap to add a word to any deck and Obo's AI builds a complete flashcard: reading, meaning, and a natural example sentence (1 coin).
Plus stability and performance improvements.
1.6.7 Jun 22
Look up Japanese words anywhere.
• Share Japanese text from any app to Obo and instantly look up words (Yomitan-style), powered by an offline JMdict dictionary.
• Indonesian meanings — see definitions in Bahasa Indonesia, not just English.
• Save with AI — tap to add a word to any deck and Obo's AI builds a complete flashcard: reading, meaning, and a natural example sentence (1 coin).
Plus stability and performance improvements.
1.6.6 Jun 7
Look up Japanese words anywhere.
• Share Japanese text from any app to Obo and instantly look up words (Yomitan-style), powered by an offline JMdict dictionary.
• Indonesian meanings — see definitions in Bahasa Indonesia, not just English.
• Save with AI — tap to add a word to any deck and Obo's AI builds a complete flashcard: reading, meaning, and a natural example sentence (1 coin).
Plus stability and performance improvements.
1.6.5 Jun 4
Look up Japanese words anywhere.
• Share Japanese text from any app to Obo and instantly look up words (Yomitan-style), powered by an offline JMdict dictionary.
• Indonesian meanings — see definitions in Bahasa Indonesia, not just English.
• Save with AI — tap to add a word to any deck and Obo's AI builds a complete flashcard: reading, meaning, and a natural example sentence (1 coin).
Plus stability and performance improvements.
1.6.4 Jun 3
This update is all about helping you keep your study habit going.
• Cram mode: practice extra cards anytime without affecting your review schedule. Use it before a test, after a long break, or when you just want more reps. You can now also cram while you're caught up.
• Session complete celebration: a friendlier finish screen when you wrap a session, with a clear next step when you're caught up.
• Mid-session pacing toast: a gentle nudge during long sessions to help you pace yourself.
• Smart Digest v2.0 notifications: smarter, locale-aware reminders that replace the old fixed reminder times. Permission is requested at the right moment, and copy now matches your app language.
• Leech protection: cards you keep forgetting are auto-buried and learning cards mix back into your main queue, so one tough card doesn't block your session.
• Fixes and polish: smoother scrolling in a few views, clearer AI wording, and small bug fixes.
1.6.3 May 22
1. Kana writing practice: stroke-order animation, auto-scoring, and recall-first session mode for hiragana & katakana (including yōon contracted sounds).
2. Fixed a freeze that could happen when generating cards with AI after accepting the data consent.
3. Improved error messaging when AI card generation fails.
4. Smaller polish: persistent hint toggle, better stroke feedback on validation failure, and tuned thresholds for finger input.
1.6.2 May 7
Writing practice for Hiragana and Katakana
1.6.1 May 6
Meet ObO Lens, scan Japanese text from your camera or photo library, see meaning and furigana instantly, and save it as a flashcard in one tap. Works on single words, full sentences, or batches.
What's new:
• ObO Lens: on-device Japanese OCR + AI lookup
• Word Picker to select words from longer sentences
• Batch Review: generate and save multiple cards at once
• Smart lookup cache + refetch button for second opinions
• Your Kana progress now syncs automatically across devices
• Fixed a login bug that occasionally reset your session
Scan it, understand it, remember it.
1.6.0 Apr 29
Fix minor bug
1.5.3 Apr 26
Smarter Spaced Repetition
Fixed edge cases in the FSRS review engine where cards could get stuck repeating every 1-2 days. Cards now progress naturally based on your actual performance.
Login Stability
Resolved an issue where some users experienced repeated authentication errors or unexpected sign-outs after logging in with Google or Apple.
Bug Fixes
- Fixed a data sync error when merging decks
- Improved error messages for clearer in-app feedback
- Cleaned up legacy code for better overall performance
1.5.2 Apr 13
Bug Fixes & Performance Improvements
- Fixed a bug where some flashcards were stuck appearing every 1-2 days even when answered correctly. Review intervals now grow properly based on your recall ability.
- Fixed "Hardest/Easiest" sort order that previously had no effect — cards are now sorted by actual difficulty.
- Fixed an error during premium deck sync that caused some content updates to silently fail.
- Internal code cleanup for better performance.
1.5.1 Apr 7
Konnichiwa! Welcome to Obo Version 1.5.0, our biggest and most exciting update for Obo Talk yet!
Here’s what’s waiting for you inside:
1. Hands-Free Commuter Mode: Busy on the train or walking? Just tap "Auto-Play" and let our immersive Japanese stories flow endlessly, just like your own personal podcast.
2. Active Shadowing Practice: Ready to speak up? Train your pronunciation using our newly designed Shadowing Mode, now featuring a precision visual countdown ring to build your confidence speaking out loud.
3. 1-Click AI Smart Add: Found a difficult word while reading a story? Open the X-Ray sheet and hit 'Smart Add'. Our AI will instantly create a full-context contextual flashcard (with furigana, translation, and examples) straight to your study deck using your AI Coins. Say goodbye to manual note-taking!
4. Spring Sakura Theme: We've refreshed the app's aesthetic with a beautiful Spring Pink theme to celebrate the season!
Update now, put your headphones on, and let's master Japanese, one by one!
1.5.0 Apr 2
Bug fixing related to syncing cards and decks for different devices
1.4.1 Apr 1
Enhanced Learning Experience
NEW FEATURES:
• Clearer AI Smart Add Interface
- Visual info button explaining how cards are generated
- Inline hints about quota system and limits
- Better understanding of free vs premium limits (5 vs 30 cards)
• Improved Beginner Onboarding
- More comprehensive step-by-step guidance
- Better explanation of app features
- Smoother transition from kana learning to deck study
• Enhanced First Deck Experience
- Guided onboarding when adding your first deck
- Clear introduction to AI features
- Better understanding of study workflow
IMPROVEMENTS:
• Refined UI typography and spacing for better readability
• Optimized button layouts and visual hierarchy
• Improved feedback messages
• Better error handling and user guidance
BUG FIXES:
• Fixed onboarding resume issues
• Improved stability during study sessions
• Better handling of edge cases in AI generation
We're constantly improving ObO based on your feedback. Thank you for learning with us!
1.4.0 Mar 26
What’s New in This Version: Introducing AI Magic!
Say hello to an even smarter and faster way to learn Japanese with Obo!
• Smart Add with AI: No more creating flashcards one by one! Just type a prompt like "JLPT N5 Verbs" or paste a list of words, and our AI will instantly generate fully-made flashcards for you—complete with Kanji, Furigana, Meanings, and Example Sentences!
• Free Weekly Quota & OBO Coins: Everyone gets 15 FREE AI quotas every week to start! Need to bulk-generate even more? Grab some OBO Coins and break the limits!
• Premium Deck Templates: Want to skip the setup completely? Download our professionally curated N5 and N4 Premium Decks using OBO Coins and start mastering new vocab right away!
• Smarter FSRS Algorithm: We've upgraded from standard SRS to the state-of-the-art FSRS (Free Spaced Repetition Scheduler) algorithm! This means better memory retention, perfectly optimized review intervals, and less time spent reviewing
• Performance Enhancements: We squashed some bugs and made your syncing and learning experience smoother than ever.
Update the app now to supercharge your Japanese vocabulary!
1.3.0 Mar 19
What’s New:
• Premium JLPT Decks: Elevate your learning with our new curated Premium N5 and N4 decks, now available via In-App Purchase!
• Enhanced Localization: Improved Indonesian translations throughout the app for a smoother study experience.
• Improved Syncing: Faster and more reliable deck synchronization across your devices.
• Performance Fixes: We’ve squashed some bugs and optimized the app to keep your learning journey seamless.
1.2.0 Mar 18
What's New We’ve completely revamped the flashcard detail view to make studying even better!
Redesigned Detail Sheet: Vocabulary meanings, readings, and examples are now beautifully organized into clear, easy-to-read sections.
Audio Pronunciation: Tap the new speaker icon in the detail view to hear the pronunciation of words and example sentences.
Furigana for Examples: Example sentences in the detail view now fully support furigana to help you practice reading.
Cleaner Formatting: Multi-line meanings and definitions are now formatted much more cleanly for easier reading.
1.0.3 Mar 5
Stunning New Progress Dashboard We’ve completely overhauled the Statistics view to make your learning journey more visual and rewarding!
1. Premium Design: A whole new "screenshot-worthy" look with beautiful floating cards, gradients, and a massive Mastery Hero card.
2. Per-Deck Breakdown: Dive deep into each deck’s performance with dedicated proportion bars and detailed status badges.
3. Interactive Ring Charts: New animated donut charts and bar graphs help you visualize your ratio of New, Learning, and Reviewed cards.
4. Card-Level Detail: You can now see the actual list of cards in each state within a deck. Perfect for tracking exactly what you've mastered!
Happy learning with ObO!
1.0.2 Feb 28
Fixing import deck and flashcard view for Bunpou.
1.0.1 Feb 24
• Announcements now appear only after you’re signed in and finished onboarding
• Offline Indonesian meanings for kanji lookup
• Paid deck titles update correctly when you switch language
• Bug fixes and polish for a smoother study experience
more Version 1.6.9 Jul 31
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