Friends of 5 and 10
The complement techniques at the base of the soroban — where the real method begins.
🎁 Early access — everything is free
Your child counts in their head faster than on a calculator
A real Japanese soroban, played as a game, 10 minutes a day. By the book, with no drilling — your child genuinely calculates in their head instead of tapping buttons.
Runs in the browser or installs as an app — offline, on phone and desktop. Progress is saved.
How it works
We take you by the hand from the very first screen and show you where to start. Nothing to figure out.
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1
Get the beads
Learn to picture a number on the abacus and master the “friends of 5 and 10” — the soroban foundation.
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2
Practise 10 minutes a day
A short session with a daily goal. Streaks and stars keep the rhythm without any pressure.
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3
Calculate in your head
We take the abacus away step by step — what stays is the mental image. That is anzan.
Level map
From 10 kyu to mastery — one technique at a time
Lessons come in order: the next one unlocks once the previous is solid. Your child always knows what to do next.
Why this is a real soroban, not “fast maths”
We don't promise “genius” or “superhuman memory”. We teach the classical Japanese method — honestly and by the book.
Seeing the beads
Your child sees the number on the abacus instead of memorising answers. That's where mental math comes from.
Kyu and dan levels
The Japanese ladder of ranks: from 10 kyu to 1 kyu and beyond. A clear route to mastery.
“On the soroban” mode
A new technique is practised with the hands first — the answer is set with the beads. Only then comes “in your head”. That's how it's taught by the book, rather than guessing at the answer.
The soroban is more than 400 years old
This isn't a fashionable “early development technique” but a school of calculation proven over centuries — and still alive in Japan today.
🇨🇳 16th century
The abacus arrives from China
The soroban's ancestor — the Chinese suanpan — reaches Japan with merchants.
🇯🇵 Japan
The soroban is born
The Japanese simplify the abacus: one “heaven” bead is worth 5, four “earth” beads are worth 1 each. Counting got faster.
🏫 Today
Taught in Japanese schools
The soroban is still on the curriculum, and kyu and dan ranks are sat as official exams.
🧠 Anzan
The abacus moves into the head
Masters move the beads mentally and add three-digit numbers faster than a calculator.
Want the longer story, with beads you can actually move? It's right there in the app — together with the interactive soroban.
You'll want to practise every day
Game mechanics keep the rhythm — without pressure or “screen time for its own sake”.
🔥 Streaks
A chain of days in a row. Missed one? A streak freeze has your back.
⭐ Stars per level
A reward for accuracy and speed — not for time spent in the app.
🗺️ Level map
The path and the next goal are visible — just like in the games they love.
🎯 Daily challenge and leaderboard
Everyone gets the same tasks — a fair contest. 🏆 The daily board resets every day: there's always a chance.
🔔 Reminders
We'll nudge you about practice so the streak doesn't burn — even when the app is closed.
⚡ Your own pace
Too easy? The “Make it harder” button raises the level. And you can set your own daily goal — anywhere from 1 to 1000 problems.
Parents can see what's going on
The parent dashboard shows practice time, accuracy and the current level for each child. One account — several child profiles, each with its own progress.
- Practice time and consistency
- Accuracy and the current kyu level
- Several children — separate profiles
- Oversight without pressure: rewards for results, not for minutes
Child has their own tablet? Connect it in a minute
No need to type your password on a child's device. Open the parent dashboard, show the code or the QR — your child enters it on their tablet, and the profile links to your account.
- Your child practises on their own device, under their own profile
- Progress shows up in your dashboard right away
- No password and no full account access in a child's hands
- Disconnect a device in one tap, any time
For adults and teens too
Flash anzan mode
Same engine, grown-up theme. Numbers flash by and you add them in your head — a workout for focus and speed. Beating a calculator is genuinely within reach. And on the 🏆 daily board you can beat everyone else.
Try flash anzanFrequently asked questions
What age is it for?
From age 6 — that's the kids' theme. Teens and adults get their own theme and flash anzan.
How much practice does it take?
About 10 minutes a day. Consistency matters more than length — that's what streaks are for.
Does it work offline?
Yes. Practice works offline, and progress syncs as soon as you're back online.
Are there competitions? Is that safe for a child?
Yes — the daily challenge leaderboard: everyone gets the same tasks, the board resets every day, and accuracy counts for more than speed. The board shows only a profile name and an emoji avatar — no last names, no email, no personal data.
How do I connect my child's device?
In the parent dashboard, tap “Connect a device” — you'll get a code and a QR. Your child enters the code (or scans the QR) on their own tablet, and their profile links to your account. No password is typed on the child's device, and progress shows up in your dashboard right away. You can disconnect a device at any time.
Is it paid?
We're in early access — everything is completely free. A subscription will appear inside the app later, along with a referral bonus program. Progress you've earned stays yours, and we'll announce the subscription well in advance.
Do I need to install anything?
Not necessarily — it opens right in the browser. But you can install it as an app on your phone or computer in one tap: you'll get an icon on your home screen and it will work offline, like any app from a store.
Start calculating in your head today
10 minutes a day — and in a couple of months mental math becomes a habit. We're in early access right now: everything is free.
Start free