Otsuri Challenge

Get smart change with minimal coins! Optimize your payment for fewer coins back. Pay ¥510 for ¥460 and get one ¥50 coin instead of many small ones. Think strategically, pay smarter!

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Otsuri Challenge - Project Story

Inspiration

In Japan, there's a unique cultural practice where people pay in a way that minimizes the amount of change they receive. When we discovered that this was a distinctly Japanese custom, we wanted to create a game that would allow people worldwide to experience this payment method and share the satisfying feeling that comes with it.

We were inspired to gamify this cultural practice to help others understand and love more about the Japanese culture.

What it does

Otsuri Challenge is a game where players must pay for items while minimizing the change they receive. The key constraint is that exact payments are not allowed, so players must strategically choose which coins and bills to use. When players make incorrect payments, they receive time penalties, creating a competitive experience that balances both accuracy and speed as players race to complete 10 questions.

Game Modes:

  • Time Attack Mode - Speed is crucial as players race against the clock
  • Practice Mode - Perfect for learning the payment strategies

The game provides the satisfaction of finding the optimal payment solution while experiencing the unique pleasure of this Japanese cultural practice.

How we built it

We built this project primarily using AI tools:

Development Stack:

  • Bolt - Main development platform
  • ChatGPT & Claude - Specification refinement and requirements definition
  • Lovart - Image generation for logos and visual assets

Development Process:

  1. Requirements Definition - Extensive conversations with ChatGPT to define project scope
  2. Initial Prototype - Input refined requirements into Bolt
  3. Specification Refinement - Used Claude to bridge gaps between vision and implementation
  4. UI Iteration - Repeatedly prompted Bolt to achieve ideal design
  5. Asset Integration - Generated and integrated game logos, currency images, coins, and bills

Interestingly, the change-giving animations and visual assets created by AI exceeded our expectations and added unexpected charm to the game, so we decided to keep them as they were.

Challenges we ran into

Technical Challenges:

  • Complex Change Logic - The calculation logic proved far more complex than anticipated
  • Natural Language Communication - Effectively communicating problems through prompts became crucial (we imposed a constraint of not viewing/editing source code directly)
  • Bug Fix Cascades - Bolt's fixes sometimes caused other issues, leading to frequent rollbacks

Resource Limitations:

  • Token Constraints - Had to strategically manage prompt efficiency
  • Collaboration Limits - One person's token allowance wasn't sufficient for thorough specification refinement
  • Migration Necessity - Had to upload to GitHub and migrate to a second Bolt environment

This experience highlighted both the limitations of solo AI development and the need for basic technical understanding even in AI-assisted projects.

Accomplishments that we're proud of

Technical Achievements:

  • Completed entire implementation using only Bolt
  • Successfully selected and utilized various AI tools according to specific needs
  • Mastered multi-person AI-assisted development - gained valuable collaboration insights

User Experience Success:

  • Change-giving animations exceeded expectations and enhanced game satisfaction
  • Effective prompt crafting - substantial progress in articulating requirements
  • Cultural Bridge - created a game introducing uniquely Japanese cultural practice to the world

We consider this a truly creative achievement.

What we learned

AI Collaboration Insights:

  • Deeper understanding of different AI tools' characteristics and strengths
  • Embrace unexpected outputs - key to successful AI collaboration is not imposing rigid expectations
  • Compatibility matters - people with overly strong preferences might struggle with AI collaboration

Development Process Evolution:

  • AI-powered development differs significantly from traditional processes
  • Rapid prototyping strength - enables more flexible project progression instead of rigid requirement definition
  • Future collaboration needs - features allowing multiple people to share screens (like Figma) will become essential

Problem-Solving Enhancement:

  • AI as brainstorming partner helps visualize challenges and approach solutions more effectively

What's next for Otsuri Challenge

Immediate Goals:

  • Global Ranking System - Enable worldwide competition
  • Multi-Currency Support - Expand to other world currencies
  • Complete Version - Include all coins/bills that were omitted due to current rule constraints

Long-term Vision:

  • Cultural Currency Education - Help players experience nuances of different global monetary systems
  • Continued AI Development - Having experienced the pure joy of creating with AI, we're excited to use Bolt for future products

The future of AI-assisted development looks incredibly promising!

Built With

  • bolt
  • chatgpt
  • claude
  • lovart
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