The stealth marketing ban and who carries it
In October 2023 the Consumer Affairs Agency designated stealth marketing as a misleading representation under the Act against Unjustifiable Premiums and Misleading Representations. Any content a business commissions or directs must be recognisable as advertising, with a clear marker such as 広告, 宣伝 or PR, not a tag buried at the end of a caption. The duty and the liability sit with the advertiser, not the influencer. That matters for generated content: synthetic customer posts, virtual influencers and UGC-style clips made by the brand are the brand's advertising and must say so. Prize campaigns tied to a purchase or shop visit fall under the same Act's premium rules, which cap prize values, while open giveaways such as follow-and-repost campaigns are not capped, so check which kind a giveaway is before it goes live.
Article 30-4, and outputs that resemble existing works
Article 30-4 of the Copyright Act allows works to be used for information analysis, which covers most AI training, provided the purpose is not to enjoy the expression and the rights holder's interests are not unreasonably harmed. Outputs are a different matter. The Agency for Cultural Affairs' 2024 guidance on AI and copyright says an output infringes where it is similar to an existing work and there is reliance on it, and reliance can be inferred where that work was in the training data. In a market built on anime, manga and game characters with active rights owners, an output that drifts towards a famous character is a real exposure. The courts also recognise publicity rights: the Supreme Court's 2012 Pink Lady decision protects the pulling power of a celebrity's name and likeness.
Keigo, three scripts and text inside images
Japanese marks politeness in the grammar itself. Brand copy is usually written in the polite desu and masu forms, with humble and respectful forms where the brand addresses customers directly; mixing registers within a piece reads as machine-made at once. Text is written in kanji, hiragana and katakana, often with Latin letters, and set horizontally or vertically, and line-breaking rules forbid starting a line with a closing bracket or a small kana. Image models still mangle kanji, so generate the picture clean and set the words as live type. Density is expected: specifications, prices, conditions and reassurance that a Western layout would cut. A spare, minimalist ad imported from Europe can read as missing information rather than as confident.
LINE, X and the local calendar
LINE is the default messaging app, and brands use LINE Official Accounts for coupons, loyalty and customer service, so a campaign needs formats for chat as well as feeds. X carries more weight in Japan than in most markets, especially for real-time trends and follow-and-repost campaigns. Instagram, YouTube and TikTok matter for younger audiences, and Rakuten Ichiba and Amazon.co.jp dominate online retail, each with its own image rules. The calendar has its own peaks: New Year and its lucky bags, Golden Week, Obon, Christmas as an occasion for couples, and White Day on 14 March. The studio's brand hub can hold the chosen politeness level and banned expressions as rules, so every generated line starts from the right register.
Updated 25 September 2026 · General information, not legal advice. Rules change, so check the current text with your legal team before relying on it.