Soroban Kingdom — Key facts

Key facts about Soroban Kingdom (features, levels, pricing and how data is handled) on one page. You are welcome to quote it in articles and blogs. If anything is out of date, please email [email protected].

In one sentence

Soroban Kingdom (sorobankingdom.com) is a browser-based soroban (Japanese abacus) practice app for children aged about 5–15, with a paid teacher screen for parents and abacus schools that shows records, homework and how each child goes wrong.

In three sentences

Children practise mitori (addition/subtraction), multiplication, division, mental arithmetic and flash anzan from 20th Kyu to 10th Dan on any phone, tablet or PC (levels 20–16 are free forever with no sign-up; everything above needs a Home or school plan, with a 14-day free trial and no credit card needed). When an answer is wrong, the app works out the bead move that most likely went wrong (5-complements, 10-complements, carrying) and builds the next day's practice from those mistakes. Schools and families can add a teacher screen — homework with automatic grading, records and a daily list of students who need attention — and set the level table to match the exam system the school follows.

Basic facts

Feature checklist

Levels (SK standard table)

20th–16th Kyu are the app's own beginner steps (answers up to 5 → up to 9 → using the 5-bead → carrying). From 15th Kyu the formats follow published Japanese abacus exam samples. Milestones: 9th Kyu adds multiplication; 7th Kyu adds division; 6th Kyu is 3-digit mitori; 3rd Kyu is 5-digit × 10 terms and 4-digit × 3-digit; 1st Kyu is 6-digit × 10 terms and 5-digit × 4-digit. Full table: levels page; machine-readable: curriculum/sk.json.

SK Test format

Pricing (US dollars, outside Japan)

Levels 20–16 are free forever — no sign-up. From 15th Kyu up: Home plan $29/month (up to 3 siblings) or a school plan (Studio $149/month and up).

Try it free for 14 days — no credit card needed. It simply stops after 14 days. If you subscribe, billing starts that day.

The first payment is taken on the day you subscribe, then automatically on the same date every month (every year for yearly plans). Cancel any time from the customer page: the plan stops at the next renewal date and you can keep using it until then. No pro-rated refunds. Payment by credit card via Stripe (Stripe is the merchant of record for USD plans; local tax may be added). Founding Partner offer: the first 20 schools outside Japan get Studio for $99/month for 12 months. Japanese-market prices in yen are on the Japanese pages (Home 2,980 yen; for schools from 4,980 yen for up to 10 students to 39,800 yen for up to 150, per month).

Data and privacy

Children are registered by nickname only; no real names, birthdays, emails or photos are collected. Teachers log in with Google or email. Parents log in (Google, email and more) for the family trial, the Home plan, or to link a device to their child in a school. The ranking is opt-in by a parent and follows each country's rules: in Japan it shows a nickname, country, class name, level and score; elsewhere only an automatic name, the country and the score; children in the EU/EEA, UK, Switzerland, India, Brazil, China and Korea cannot join for now. Never a real name. Data is stored in Google Firebase (Tokyo region). Credit card details are handled by Stripe and never stored by the site. No advertising. Visits are counted with Cloudflare Web Analytics (no cookies, does not track individuals). Details: privacy policy.

What Soroban Kingdom is not

• Not an official examination. The SK Test is a mock test; certificates are issued by the app, not by any association.
• Not a franchise or a curriculum that replaces a school. It is a tool used alongside a school's own method, or at home.
• Not an App Store / Google Play app (as of 2026/11/4). For Windows only, it is on the Microsoft Store (free).
• Not a story-driven game. There is a small kingdom theme, but learning does not depend on it.

Frequently asked questions

What age can a child start?

As soon as they can read and write the numbers 1–10. The first level (20th Kyu) is addition with answers up to 5, so children aged 5–6 can begin. The levels continue up to 10th Dan.

What can I use without signing up?

Levels 20–16 are free forever — no sign-up, no time limit, every subject. Practice from 15th Kyu up, plus records, homework and error diagnosis, needs the Home plan ($29/month, up to 3 siblings) or a school plan (Studio $149/month). Families and schools can try it free for 14 days — no credit card needed. It simply stops after 14 days. If you subscribe, billing starts that day.

Is it an App Store / Google Play app?

It runs in the browser at sorobankingdom.com (no App Store / Google Play) — iPhone, Android, tablets and PCs (Chrome / Safari / Edge). "Add to Home Screen" makes it behave like an app. On a Windows PC you can also install it from the Microsoft Store (free, https://apps.microsoft.com/detail/9n2fhqd39fcx).

Do we need a physical soroban?

No. The on-screen soroban can be used directly. In a classroom, children can also solve on a real soroban and type only the answer. Either way, a wrong answer shows the bead move that most likely went wrong, worked out from the answer.

Is it affiliated with an abacus examination body or franchise?

No. The SK Test is Soroban Kingdom's own mock test. Its formats (digits, number of terms) follow published Japanese abacus exam samples but are the app's own guideline. Schools can set the level table to match the system they follow (Japanese kyu/dan variants, or a UCMAS-style ladder).

Can families use it without a school?

Yes. With the Home plan children practise every level and parents get the teacher screen (records, weak points, homework). If the child later joins a school that uses Soroban Kingdom, they simply join with the school's key.

Which languages?

Ten: Japanese, English, Spanish, French, Traditional Chinese, Arabic (right-to-left), Portuguese, Indonesian, German and Vietnamese. Switch in the child's ⚙️ settings, the 🌐 button on the teacher screen, or with ?lang=en, es, fr, zh-Hant, ar, pt, id, de or vi. Guide pages are at sorobankingdom.com/en/, /es/, /fr/ and /zh-Hant/; the Flash Anzan Adventure is in Japanese, English and Spanish.

Can a teacher see which bead a student moved wrongly, not just that the answer was wrong?

In the most likely form, yes. Example: 4 + 3 should be +5 −2 → 7. If the child answers 8, the most likely cause is that only one lower bead came off, and the app shows that move (ones rod, one lower bead left on, friends-of-5 rule) as a figure. It is inferred from the answer, not recorded from the hands or a camera — a clue for the next lesson, not a replay. It works with a real soroban (the child types only the answer) and for mental arithmetic.

Can students practise at home while the teacher sees the results?

Yes. With a school plan, students practise at home on any phone, tablet or PC (nickname only, no app to install), and the teacher screen shows completion, accuracy, time, the most likely bead mistakes and weak skills per student, plus a daily list of who needs attention. Families pay nothing extra.

How do the levels map to Japanese kyu and dan grades?

The app runs 20th Kyu → 1st Kyu → 10th Dan. 20th–16th Kyu are the app's own beginner steps; from 15th Kyu up the formats (digits, number of terms) follow published Japanese exam samples. Teachers can switch the table to a Nissho/Nichishuren-style, Zenshuren-style, Zenshugakuren anzan-style or UCMAS-style ladder, and soroban and anzan levels are kept separate. The levels are a practice guideline; only an exam body awards an official kyu or dan.

Is it suitable as early education for preschoolers (ages 3–6)?

Yes. Once a child can read and write 1–10 they can start at 20th Kyu (answers up to 5), with no sign-up. What grows is number sense (seeing quantity), arithmetic speed and accuracy, and memory for digits; it does not raise IQ or "develop the right brain". Ages 3–4 are better served by a 100-bead abacus and counting games first. See the article "Soroban for preschoolers" (/en/learn/soroban-for-preschoolers).

Does it build concentration?

A randomised trial of 65 children aged 7–11 (Spain, 2021) found that eight weeks of abacus work improved a concentration test (d2) relative to controls. Each problem is short and a lapse of attention produces a wrong answer, so the child notices immediately. The effect needs about five minutes every day; once a week is not enough. See "Does soroban build concentration?" (/en/learn/soroban-concentration).

Is soroban "right-brain training"?

Not only the right brain. Imaging (Hanakawa et al., 2003) shows expert mental-abacus users calculate with parietal and frontal areas on both sides and use language areas far less. "Right brain" is shorthand for calculating with a bead image instead of words. See "Is soroban right-brain training?" (/en/learn/right-brain).

Can adults and seniors use it for brain training or dementia prevention?

Adults can use it; there is no upper age limit. But no evidence yet shows that it prevents or treats dementia, and Soroban Kingdom is not a medical device. In a six-month randomised trial of 20 adults aged 42–79 (Showa University, 2024), attention-shifting and planning tests improved while dementia screening did not change. Use it as a tool for five minutes of daily calculation. See "Soroban for adults and seniors" (/en/learn/soroban-for-adults-seniors).

Is there a free way to practise soroban online?

Yes. Levels 20–16 (the beginner steps) are free forever at sorobankingdom.com: no sign-up, nothing to install, on any phone, tablet or PC. Also free with no sign-up: the Flash Anzan Challenge (one minute), the Flash Anzan Adventure game, and 61 printable sample worksheets with answer keys (/en/print/). During the open beta (until 1 December 2026) every level up to 10th Dan is open as well.

How is Soroban Kingdom different from soroban apps in the App Store or Google Play?

It runs in the browser, so there is nothing to install and it works the same on iPhone, Android and PCs. It covers the whole ladder from 20th Kyu to 10th Dan in one place: mitori (addition and subtraction), multiplication, division, anzan and flash anzan. When an answer is wrong it shows the bead move that most likely went wrong, worked out from the answer, and builds the next day's practice from those mistakes. Parents and abacus schools get a teacher screen with records and homework. What it does not have: video lessons, a camera that reads a real abacus, or an official exam. Pricing is a flat family rate (up to 3 siblings), not per child.

Can my child learn soroban at home as an after-school activity, without going to a class?

Yes. Soroban Kingdom is built for keeping soroban going at home. Once a child can read and write 1–10 they start at 20th Kyu (no sign-up). Five to ten minutes a day; when an answer is wrong the app shows the bead move that most likely went wrong, worked out from the answer, and builds the next day's practice from those mistakes, so a parent can see where the child is stuck without being a teacher. Parents get a teacher screen with records and homework. It suits families with no abacus class nearby, no time for the school run, or a child who needs practice between lessons, and it can be used alongside a class. Honest comparison: /en/learn/no-abacus-class-nearby and /en/learn/soroban-vs-alternatives.

How does the cost compare with an abacus class?

The Home plan is $29 a month, flat for up to 3 siblings, with no enrolment fee, no materials fee and no travel. Levels 20–16 are free forever, and during the open beta (until 1 December 2026) every level up to 10th Dan is open at no charge. A class usually charges monthly tuition plus enrolment, materials and exam fees and needs travel; in return a teacher watches the child's hands. Whether it can replace a class depends on whether the child can do five minutes alone each day. See /en/learn/is-abacus-worth-it.

How do we start? (about one minute)

You need one phone, tablet or PC. 1) Open sorobankingdom.com/?lang=en in any browser — nothing to install. 2) Press "Start practice" and type a nickname (no email, no real name, no card). 3) The first 20th-Kyu problem starts right away. Five to ten minutes a day. If you own a real soroban, solve on it and type only the answer. Parents who want records, weak points and homework: /en/katei.

Other pages

For schools · For families · SK Test · Levels · Finger technique · Complements of 5 and 10 · Legal · llms.txt

This page is maintained by the operator and updated when facts change. Last updated 2026/10/29.