Japan Premium Phone Number Lookup Tool (Rakuten, docomo, au, SoftBank, ahamo, povo, UQ, Y!mobile, etc.)
Most carriers in Japan assign phone numbers randomly when you sign up — it’s pure luck. Getting a number you actually like is pretty much impossible.
Rakuten Mobile is the exception though. When you apply on their website, you can pay to choose your own number. But the selection process is really clunky — you can only see a handful of numbers at a time. Trying them one by one is painfully slow, and the connection drops constantly. So I built a tool to search for premium numbers with custom criteria.
I categorized premium numbers into four tiers:
S - Ultimate — Once-in-a-lifetime finds
- AAAA quadruple repeats (like 8888, 6666)
- 4-digit sequential numbers (like 5678, 8765)
A - Rare — Don’t hesitate if you find one
- AAAAX (88889) or XAAAA (18888) — almost a full quad
- AAA triple repeats (ending in 888, 666)
B - Classic — Easy to remember, nice patterns
- AAAB triple-same (8886), AABB double pairs (8866)
- ABAB alternating (8686), ABBA palindrome (8668)
C - Entry Level — Good enough for daily use
- 3-digit sequential (678, 876)
- Lucky numbers (combos like 1688, 1888, 5188)
11 pattern rules in total, covering pretty much every type of premium number out there.
Some Handy Features
Digit Exclusion: In Japanese, 4 is pronounced “shi” which sounds like the word for death, and 9 is pronounced “ku” which sounds like suffering. Many people in Japan consider these unlucky. The tool lets you exclude any digit from 0-9 individually — just check the box and no numbers containing that digit will appear in results.
Custom Suffix: If the preset rules aren’t what you’re after, you can type in any specific ending you want — like a birthday (0226), anniversary (1225), or any meaningful number.
Super Highlight: If you select the AAAAX rule (4 identical digits + 1 different), Rakuten only lets you search by the last 4 digits. But if the returned number happens to have the same digit right before those four, it’s actually AAAAA — a five-in-a-row! The tool automatically detects this and marks it with a red SUPER tag.
Filtering and Search: After searching for a while, the results list can get pretty long. There are category tags at the top with counts for each type — click one to filter. There’s also a search box to look for specific digit patterns in your results.
What to Do After Finding a Number
The tool itself only searches — it doesn’t reserve or purchase numbers. Once you find a number you like, you’ll need to go to the Rakuten Mobile website and apply through their normal sign-up process. Just enter the number you found during the number selection step. Note that Rakuten charges 1,100 yen for a custom number, but I think it’s totally worth it if you find one you love.
What About Other Carriers?
If you don’t want to stay with Rakuten Mobile and prefer docomo, au, SoftBank, ahamo, povo, UQ, Y!mobile, or others, you can use Japan’s MNP (Mobile Number Portability) system.
Here’s the approach: Get a premium number on Rakuten Mobile first → use it for a while → MNP transfer to docomo / au / SoftBank / ahamo / povo / UQ / Y!mobile or any budget SIM carrier you like.
That’s exactly what I did, haha.
Why Isn’t This Tool Public?
I’m not sure whether a tool like this complies with Rakuten’s terms of service. It only performs lookups without any modifications, but it’s still an unconventional method. To be safe, I’m not planning to open-source it for now.
If I can confirm there are no compliance issues down the road, I’ll release the code repository right away.
How to Use This Tool
If you need a number search, feel free to leave a comment or send me an email with:
- What kind of number you want — for example, “ending in 8888”, “want a sequential number”, “containing 168”, “no 4s or 9s” — the more specific, the better
- Your email address
I’ll search for numbers as soon as I can and send you the organized results. I’ve built a fully automated workflow — once I input the number rules and email, it sends the results automatically.