Bitbank Draws the Line
The exchange posted a formal notice citing Japan’s longstanding gambling prohibitions. Bitbank said it would move to suspend any account where deposits or withdrawals connected to prediction market services, or services suspected of being related to them, are detected.
The suspension covers all account functions without exception.
Affected users would lose:
- Login access
- Crypto asset deposits and withdrawals
- Japanese yen withdrawals
- All buying and selling of crypto assets
Bitbank also stated it would not be responsible for damages resulting from account suspension measures.
Why Japan Treats Polymarket as Gambling
Polymarket operates as a decentralized event-contract platform where users stake cryptocurrency, typically USDC, on outcomes such as election results, economic indicators, or sports events.
Under Japan’s Penal Code, Article 185, gambling is defined as staking something of value on an uncertain real-world outcome. The narrow exception covers only trivial, non-monetary social bets. Crypto-settled event contracts do not qualify.
The National Police Agency has stated explicitly that accessing and participating in online gambling operated legally abroad remains a crime for Japanese residents. That guidance applies regardless of how a platform labels its product.
Prediction markets hold no authorization under Japan’s Financial Instruments and Exchange Act, and the Financial Services Agency has issued no specific guidance creating a legal path for them.
Polymarket Already Blocks Japan
Polymarket has geoblocked its web frontend for Japanese IP addresses, placing Japan among approximately 34 restricted jurisdictions. The platform explicitly prohibits VPN workarounds as a Terms of Service violation.
Rather than operate in legal uncertainty, Polymarket has appointed a Japan representative and is lobbying for regulatory authorization. The company is targeting government approval around 2030.
What Suspension Means in Practice
Bitbank’s notice specifies a full account freeze, not a partial restriction. A suspended user cannot log in, move funds, convert assets, or withdraw yen. The exchange offered a limited remedy for mistaken suspensions: users not using prediction market services can submit an inquiry form for review.
That carve-out matters because automated detection based on counterparty wallet addresses can sometimes flag unrelated transactions.
Criminal Exposure Remains Real
Japanese residents who participate actively face more than account inconvenience. Criminal penalties under Article 185 include fines of up to 500,000 yen. Habitual activity carries heavier sanctions. Enforcement has intensified since 2025 amendments to Japan‘s Basic Act on Countermeasures Against Gambling Addiction, which specifically targeted illegal online gambling and produced record enforcement actions.
No large-scale enforcement targeting Polymarket users specifically has been widely reported as of mid-2026, but the legal framework puts active users at ongoing risk.
The Broader Picture
Japan’s gambling restrictions trace to Meiji-era law and remain tightly controlled. The government authorizes public horse racing, bicycle racing, and motorboat betting, plus government-operated lotteries. Online gambling outside those channels remains broadly prohibited.
Domestic workarounds exist, including points-based prediction models that decouple participation from direct cash payouts, but fully decentralized crypto-settled prediction markets face a steep path to legalization.
Bitbank’s notice makes clear that Japanese users should treat any connection to Polymarket or similar platforms as an account-level risk, effective immediately.
