OptQC Corp., a Tokyo-based optical quantum startup, has partnered with NTT, Inc., a telecommunications giant, to develop a 1-million-qubit-class optical quantum computer through a capital and business alliance agreement1. This collaboration aims to accelerate the development and commercialization of a fault-tolerant quantum computer, with NTT making a strategic equity investment in OptQC. The agreement establishes a medium- to long-term framework for cooperation on hardware architecture and other key areas. The goal is to build a massive optical quantum computer, surpassing current capabilities. This partnership is significant because it brings together OptQC's expertise in optical quantum computing and NTT's resources and experience in telecommunications. The development of a 1-million-qubit-class quantum computer has the potential to revolutionize various fields, including cryptography and optimization problems, so practitioners should pay close attention to this alliance as it may lead to breakthroughs in quantum computing.