AI Engineer (Natural Language Processing)

This role designs, develops, and deploys AI systems that support the development and live operation of game content. The work uses natural language processing, machine learning, large language models, and the substantial data generated by live games. Responsibilities cover the full project lifecycle, including selecting models, designing prompts, optimizing user experience, and evaluating system performance.

The engineer is also expected to track current trends in LLMs and related services and share relevant knowledge with the team and within the company. The role operates in a cross-functional environment and involves cooperating with others to solve problems and support game-content development and operations.

Required qualifications include a basic understanding of natural language processing, machine learning, and LLMs; experience addressing problems with natural language processing technologies, including LLMs, with proof-of-concept experience accepted; and development experience using Python, R, or a similar programming language. Communication ability and an emphasis on teamwork are also required.

Preferred experience includes evaluating the performance of large language models and conducting training or fine-tuning to improve performance. Experience improving generative accuracy through prompt-engineering approaches such as RAG or ReAct, and experience developing conversational AI systems such as chatbots, are welcomed. A degree in a related field at bachelor’s level or above, or equivalent professional experience, is also welcomed. Experience with cloud services such as AWS, GCP, or Azure, understanding of database technologies such as SQL, and understanding of AI ethics are additional preferred qualifications.

The position is based at offices in Shibuya or Meguro, Tokyo. Working hours are 10:00 to 19:00, including eight scheduled working hours and a 60-minute break from 13:00 to 14:00. Average monthly overtime is stated as approximately 18.5 hours based on 2025 results. The standard employment type is full-time permanent employment, although the posting notes that contract or outsourced arrangements may also apply.

Annual compensation is listed in the authoritative job data as JPY 4.5 million to JPY 12 million. The posting states that compensation is determined according to experience, ability, and company rules. A semiannual performance incentive is available, and the annual compensation includes scheduled overtime and late-night work allowances.

Benefits and support include health, employment, workers’ accident compensation, and employees’ pension insurance for applicable permanent employees; training and skill-development programs; mentoring support for new and second graduates; influenza vaccination; an on-site massage service; free soft drinks; lunch support; babysitter discounts; brain screening; housing and moving allowances; child allowances; and a corporate defined-contribution pension plan. The posting states that holidays, insurance, and benefits may differ for outsourced contracts and that side jobs are prohibited.