Press Releases 2025
In recent years, Japanese companies have rapidly adopted generative AI in their advertising and marketing activities, from target research and analysis to creative production and effectiveness measurement. However, many of the models currently in use are based on large language models (LLMs) developed overseas, making it difficult to generate advertising copy that captures the subtleties and nuances of the Japanese language.
To address this challenge, Dentsu and Dentsu Digital will combine their copywriting expertise and know-how in AI advertising solutions such as "AICO2"*1 with the Japanese language-focused LLM "Sarashina"*2, which is being developed by SB Intuitions on SoftBank's AI computing infrastructure. The four companies will aim to develop a generative AI that can create compelling Japanese advertising copy which faithfully expresses Japanese linguistic nuances.
Specifically, the project will implement additional training on "Sarashina" using real advertising copy (Supervised Fine-Tuning [SFT]*3 and Direct Preference Optimization [DPO]*4) to enhance expressive performance and enable richer creative outputs. The AI will also learn to adjust the strength of tone, allowing it to adapt word choice to the objectives and target audience of marketing communications. Furthermore, the AI will be equipped with self-evaluation functions to refine its outputs, thereby improving the accuracy of copy generation and enhancing the overall quality of Japanese copywriting.
Through this joint research, AI trained on copywriters' creative processes will combine imaginative thinking with advanced linguistic expression, making it possible to apply the outcomes not only to copywriting but also to advertising tasks such as naming and narration, verbalization of ideas and concepts, and the advancement of marketing research and analysis.
The four companies will continue to expand the possibilities of collaboration between humans and AI, creating new solutions and innovations that bring value to diverse clients and society.
- [Notes]
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- *1AICO2: An AI advertising copy generation tool developed by Dentsu in 2024, trained on the thought processes of Dentsu copywriters.
- *2Sarashina: A Japanese language homegrown generative AI under development by SB Intuitions.
- *3Supervised Fine-Tuning (SFT): A training method in which AI learns basic knowledge and desirable behaviors using question-and-answer pairs created by humans.
- *4Direct Preference Optimization (DPO): A training method in which AI learns human preferences and intentions to produce optimal results.
- *1
Roles of Each Company
| Dentsu | Evaluation of generated advertising copy |
|---|---|
| Dentsu Digital | Provision of training data for the Japanese copywriting-specialized AI |
| SoftBank | Provision of AI computing infrastructure |
| SB Intuitions | Development of the Japanese copywriting-specialized AI |
Company Profiles
Dentsu Inc.
Dentsu provides a wide range of solutions covering the entirety of clients' marketing activities, while also supporting transformation in advertising development, customer experience design, marketing infrastructure, and broader business innovation. By combining diverse capabilities beyond the marketing domain, Dentsu delivers integrated solutions that contribute to the sustainable growth of clients and society.
https://www.dentsu.co.jp/en/
Dentsu Digital Inc.
Guided by the purpose, "Inspire people, create new value, and improve how the world works", we are committed to realizing the full potential of new solutions that can emerge from the joining of creativity and technology closer to people's hearts and minds. As a strong partner for our clients' business evolution, our goal is to aim for long term "transformation and growth" both within the economy and across society through creating new value together.
https://www.dentsudigital.co.jp/en/
SoftBank Corp.
Guided by the SoftBank Group's corporate philosophy, "Information Revolution – Happiness for everyone," SoftBank Corp. (TOKYO: 9434) operates telecommunications and IT businesses in Japan and globally. Building on its strong business foundation, SoftBank Corp. is expanding into non-telecom fields in line with its "Beyond Carrier" growth strategy while further growing its telecom business by harnessing the power of 5G/6G, IoT, Digital Twin and Non-Terrestrial Network (NTN) solutions, including High Altitude Platform Station (HAPS)-based stratospheric telecommunications. While constructing AI data centers and developing homegrown LLMs specialized for the Japanese language with 1 trillion parameters, SoftBank is integrating AI with radio access networks (AI-RAN) with the aim of becoming a provider of next-generation social infrastructure.
https://www.softbank.jp/en/
SB Intuitions Corp.
As a subsidiary of SoftBank Corp., SB Intuitions focuses on research and development of generative AI and related services centered on the "Sarashina" series of Japanese-specialized large language models, aiming to achieve the best performance in Japanese among domestic LLMs. Leveraging one of Japan's largest computing infrastructures and stringent domestic data management, the company has released high-performance models such as "Sarashina2-70B" and the multimodal model "Sarashina 2-Vision," accelerating the social implementation of generative AI through industry-academia collaboration.
https://www.sbintuitions.co.jp/en/
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