Japan Smart Chain | Hackathon Bounty

📖 About

Japan Smart Chain (JSC) is an Ethereum Equivalent Layer 1 blockchain, validated onshore in Japan by Japanese industrial leaders, and optimized for Japanese regulations.

Mizuhiki ID is an on-chain universal ID issued with the simple tap of a My Number Card. Mizuhiki ID includes an on-chain KYC proof in the form of a Soulbound token, enabling users to engage with regulated activities without revealing personal information to multiple intermediaries.

docs.kaigan.jsc.dev Testnet/Testflight Access Request Form Token Direct Minting Form

📜 Bounties

Use “Mizuhiki Verified” Soulbound Token to create either a:

1. Compliant, Privacy-Preserving DeFi application

This track has a more technical focus, perfect for teams wanting to implement latest cryptography protocols, or simplify existing, known solutions.

🥇Winner prize: 💵US$1500

2. Ticketing application

This track has more of a user experience and design focus, perfect for teams wanting to simplify onboarding and retention of users for their web3 application.

🥇Winner prize: 💵US$1500

Other prizes up for grabs:

💎 Special Award (💵US$500)

For a unique idea that, while not fully developed into a winning solution for (1) or (2), strongly resonates with JSC’s mission of creating “magical” user experiences on web3.

📣 JSC Founders and Investors

One of the most exciting prizes - beyond cash - is the opportunity to pitch directly to JSC Founders and Investors shaping the web3 space. This is your chance to turn a weekend project into a commercially viable idea - gaining visibility with the people who can help you take it to the next level.

As the Mizuhiki Verified Soulbound Token is only available on JSC, participants will have to use the Ethereum-equivalent JSC testnet “Kaigan”. Please contact us at developers@japansmartchain.com to gain access to the testnet, or find us in-person at the EthTokyo conference or hackathon.

✅ Qualification Requirements

Judging is based on the value of your idea, technical execution, and use of Mizuhiki Verified Soulbound Tokens (SBTs).

Core Requirement

Your project must integrate Mizuhiki Verified SBTs on the JSC Kaigan testnet to:

  • Create apps or tokens that are compliant with Japanese regulations; and/or

  • Create apps that better facilitate loyalty and ticketing applications.

Submission Package

To qualify, each team must submit all of the following within 48 hours:

1️⃣ GitHub Repository containing:

☐ Smart contracts, scripts, front-end code, tests, and documentation.

☐ A complete and professional README file (see structure below).

2️⃣ README File with these sections clearly labeled:

☐ A one-sentence summary of your project.

☐ How you used Mizuhiki Verified SBT in your project.

☐ Setup and testing instructions that can be followed without assistance.

☐ A link to a short video demo (≤ 3 minutes), or a slide deck.

☐ Next steps you’d like to take to improve or deploy your project.

3️⃣ Team Summary:

☐ A short description of each team member and their role.

Demo & Presentation

Each team must provide either:

☐ A video demo (≤ 3 minutes) uploaded by the deadline, or

☐ A live in-person presentation during judging.

🚨 Disqualification Triggers

Projects will be disqualified if they:

  • Do not use Mizuhiki Verified SBTs on the JSC Kaigan testnet.

  • Fail to submit a complete GitHub repository with README, demo, and team summary.

  • Miss the submission deadline.

⚖️ Judging Criteria

🏆 Privacy-Preserving DeFi

Public blockchains cannot achieve mainstream adoption without robust privacy. Yet current privacy tools, such as mixers like Tornado Cash or Cyclone, are associated with illicit activity and face regulatory crackdowns. The challenge is to create privacy-preserving solutions that protect users while remaining compliant.

The Japan FSA states1:

取引記録が公表されるため、プライバシー、守秘義務、消費者保護に関する懸念が生じる
Public blockchains mean that] transaction records will be made public, raising concerns about privacy, confidentiality and consumer protection

Ref: FSA (slide 15)

Using Mizuhiki ID, we can solve the compliance part, but correlational privacy risk is still a major concern.

For example, a person using an EOA for a stablecoin transaction at the convenience store may then have their EOA “doxxed” by the convenience store attendant. 

At the same time, tooling like privacypools.com or Tornado Cash do not offer enough regulatory certainty or safety for “normal” users.

We want to see DeFi tooling that uses the Mizuhiki Verified Soulbound Token to filter out non-KYCed accounts, but also help to preserve privacy by obfuscating transaction amounts, sender/receiver addresses.

Tooling Ideas Possible Features
Smart Contract Accounts

Enable KYC’ed users to access DeFi with enhanced privacy and flexibility by binding Mizuhiki Verified SBTs to smart contract accounts instead of EOAs, unlocking programmable identity, multi-address support, and optional privacy-preserving interactions.		 Privacy wallet like Wasabi -Wallet.

Embedded Smart Contract Account SDK.

AI agents / Object Capability (OCap).
Privacy Pools

Privacy pools can be thought of as a coin mixer (like Tornado Cash) + a compliance gateway. We encourage developers to leverage Mizuhiki Verified SBT to form the compliance gateway.		 Denomination Dependent.

UTXO / Account Based.

Interaction with Smart Contract Accounts.

Easy User Experience.

Yielding Privacy Pools.
Potential Use Cases

  • B2B, Trade Finance

  • Salary Payments

  • General DeFi (UniSwap, SushiSwap, Trading)

  • Yielding or staking platforms

  • Investment Platform

Recommended Reading: 
⚖️ Judging Criteria
Completeness of main project (setup, end-to-end testing) 20%
Use of modern cryptographic techniques or research (ZKPs, FHE) to improve (1) robustness of privacy, (2) computation speed and (3) code simplicity 20%
Seamless User Experience (onboarding, retention, easy for non-technical users) 40%
Real-world utility: solving a meaningful compliance problem whilst being integrated effectively with web3 (technologies) 20%

🥇Winner prize: US$1500

🏆 Ticketing

Use the Mizuhiki Verified SBT to create a seamless user experience for ticketing (for real-world or virtual concerts, gaming, or loyalty).

This track is slightly less technical than (1), with judging criteria more focused on a seamless, “magical” user-experience. 

Today’s Ticketing Problem: 

Today’s ticketing is plagued by fraud, scalping, high fees, and a lack of transparency;  hurting both issuers and fans. Issuers lose control over resale markets and fan relationships, while fans face fake tickets, inflated prices, and zero loyalty rewards.

Web3 could solve this by making tickets verifiable, programmable, and ownable: issuers can enforce resale rules, capture royalties, and engage fans directly, while fans gain guaranteed authenticity, fairer pricing, and lasting value through NFT-based collectibles and rewards.

Ticketing applications may include the following features:

  • 💱 Limiting resales

    • Price Caps: Event organiser can stipulate caps on resale prices in a ticket smart contract, preventing premature resales or scalping.

  • 🎟️ Transfer without double spend: as soon as a ticket is transferred or resold, the ticket QR/barcode changes on both the (digital) ticket, and the ticketing platform’s (blockchain) database, so that the purchaser is guaranteed entry.

  • 👾 Fan Unlocks: Attendance to certain events or purchase of merchandise can unlock “super-fan” opportunities and/or events. Use Mizuhiki to verify the user’s identity.

  • 💳 Cheap payment methods:

    • Send stablecoin payment to a ticketing app → easy one click, finalised payment + easy refunds if show is cancelled. 

    • Accumulate points on app or transfer points to other ticketing providers.

  • 🔐 Offline Usage: Use ZKs to prevent double-spend problem without internet, or prove eligibility to certain events.


Fan community building features:

Tickets can provide participation to certain activities in DAOs, such as voting and reward distributions. Ticketing apps that add a “DAO” feature may have a chanc to be featured with the Japan DAO Association.

Potential Use Cases

  • Integration with major ticketing backends in Japan

  • Create Japan’s #1 end-to-end ticketing or rewards platform

⚖️ Judging Criteria
Completeness of main project (setup, end-to-end testing) 20%
Innovative Design & Presentation of Application 20%
Seamless User Experience (onboarding, retention, easy for non-technical users) 40%
Real-world utility: solving a meaningful compliance problem whilst being integrated effectively with web3 (technologies) 20%

🥇Winner prize: US$1500