This document provides an overview of an EU-Japan smart city project and a city platform as a service solution. The project aims to develop an open social city platform, deploy the platform as a service, empower citizens with their data, validate the platform with use cases, and create blueprints for other cities. The document discusses what makes a smart city, the project partners and objectives, the platform architecture with different layers, and benefits for cities. It also examines success factors like stakeholder involvement, openness and data sharing, and upscaling potential. Example use cases presented are smart transportation, emergency care, water management, events, and government. The last section describes a Sapporo use case focusing on improving services for tourists using open data