Localizing Your Vertical Video Ads
for Japan in Four Stages

01📈 Japan's mass audience is already on vertical video

First, let's confirm the numbers behind vertical video advertising in Japan. According to Dentsu's "2025 Advertising Expenditures in Japan," internet advertising reached ¥4.0459 trillion of the ¥8.0623 trillion total, a 50.2% share. More than half of ad spend has already moved online.

Looking at video specifically, CyberAgent's survey puts Japan's video ad market at ¥885.5 billion in 2025 (122.2% of the prior year). Of that, vertical video ads reached ¥204.9 billion (155.9% of the prior year), growing faster than video advertising overall. Vertical video ads are forecast to reach ¥277.1 billion in 2026 and ¥564.8 billion in 2029.

The audience is broad, too. In MIC's FY2025 survey (ages 13–79), usage rates were YouTube 81.5%, Instagram 54.8% and TikTok 36.7%. Weekday internet use averaged 183.9 minutes a day, ahead of real-time TV viewing at 156.1 minutes. TikTok reports about 49.5 million monthly users in Japan (as of end of May 2026, company figure excluding overlap with TikTok Lite). The survey methods differ, so the numbers can't be compared directly, but it is clear that vertical video is not just for young people: it has become an ad surface that reaches Japan's mass audience.

02🌐 Why translation alone underperforms

Take an ad that wins at home, add Japanese subtitles and run it. It is a natural first move, but it often falls short. The reason is that many of the factors that drive ad performance sit outside the literal meaning of the words.

• How the ad opens: what you show first. The kind of opening that feels trustworthy in a Japanese feed can differ from your home market
• The direction of the message: what you promise. A way of promising that worked at home can feel pushy in Japan
• The speaker and the setting: who is talking, in what room, wearing what. Do viewers feel the speaker is "someone like me"?
• Text volume and readability: Japanese has a different text density from English. Literal subtitles get long and often don't fit on screen

None of these are fixed by better translation. The details of first-two-second hooks, adapting message angles, subtitle design, choosing talent, ad length and testing are covered in our separate article, "Anatomy of Winning Vertical Video Ads in Japan." This article focuses on the process: in what order, and how far, to rework your ads.

03🪜 The four stages of localization

Reworking home-market ads for Japan can be divided into four stages depending on how much you change. Each step up takes more effort and cost, but also widens how far you can tailor the ad to Japanese viewers.

1. Translation

The fastest and cheapest way to start. For footage that communicates value on its own, such as gameplay or app screen recordings, translation alone can sometimes get a reasonable response. Ads where a speaker talks to camera, or that rely on cultural context, tend to feel off when only translated. Treat this stage as a "first probe" to check, on a small scale, whether there is any response in Japan.

2. Localization

This stage keeps your home-market footage but works on the parts translation cannot fix. The core tasks are swapping the first few seconds for a Japan-specific opening, changing how the message is phrased, and rebuilding subtitles around Japanese text volume. Because you reuse your existing assets, you can test for Japan with less effort than new production.

3. New production for Japan

Shoot from scratch with Japanese talent, locations and scripts. The key is not to "copy" your home-market ad, but to put into words why it won at home and carry that over. Did it win on low price, or on how easy it is to get started? If the reason it won is the same, the way you show it can change completely for Japan.

4. Scaling

Once you find a winning pattern in Japan, create variations that change the combination of opening, speaker and message, and increase spend. Response drops if you keep running the same ad, so the core of this stage is a setup that keeps producing and rotating variations. Formats born in Japan can sometimes work in other Asian markets as well.

04🧭 Which stage to start from

You don't have to go through the four stages in order from 1. Choose your entry point based on the nature of your product, the footage you already have, and your budget and timeline. Here are the guidelines the du-o team uses (practical guidelines, not statistics).

Signs it's time for the next stage

• Translation → localization: you get views, but they don't lead to the next action (install, sign-up). Many viewers drop off in the opening
• Localization → new production: even with a new opening and message, the speaker or the look of the footage still stands out awkwardly in Japanese feeds
• New production → scaling: you have found a format that hits your target on metrics close to business results (CPA, CPI and so on)

Make these calls on metrics close to business results, not upper-funnel metrics such as views. That is why it pays to finish the measurement setup covered in the next section first.

05📦 What to hand your Japanese production partner

When you commission a Japanese production partner, the quality of the information you hand over at the start makes a big difference to how accurate the first few ads are. Put the following five items together in one document.

1. The brief

• An overview of the product and the users you want to reach in Japan (age, daily-life context, pain points)
• The platforms (TikTok, Instagram, YouTube and so on) and placements
• The number of ads, lengths and delivery formats you need, and when you plan to start running them
• Brand rules to follow (logo usage, colors, tone of voice)

2. Your home-market winners and why they won

Don't just send video files. Add a note on why you think each one won: on which metric it won, and which opening, message or speaker you believe made the difference. If you have losing ads, send those too. If you have hypotheses such as "we want to try this in Japan" or "we think this one is specific to our home market," share them as well.

3. Banned expressions and review notes

• Words and claims your headquarters' legal or brand team prohibits
• A policy of not using numbers or comparisons you can't substantiate (such as "No. 1" or "cheapest")
• Any expressions that have been rejected under platform ad policies in the past, with details

Also include a label that shows the content is an ad (such as "PR"). For details, check the Consumer Affairs Agency's materials or consult a professional.

4. Your measurement setup

Share which outcomes you measure, with which tools, and how far. For apps, that means your measurement tool (MMP) and event definitions; for e-commerce or web, your tags and conversion definitions. If you are adding new events for Japan, finish the setup before ads start running.

5. KPIs

Decide in numeric terms what counts as a "win." Agree with your production partner on targets for CPA, CPI, ROAS and so on, and on when you will judge (how much delivery before making a call). Japanese market rates can differ from your home market, so it is fine to set a range for your targets at first.

06🌏 Working across languages and time zones

Language and time zones will always be hurdles between an overseas headquarters and a Japanese production team. Agreeing on how you will work at the outset greatly reduces rework.

Check scripts with back-translation

Once the Japanese script is ready, have it translated back into English (or your headquarters' language) to check it. Back-translation serves two purposes: catching shifts in meaning, and letting approvers at headquarters understand the content well enough to decide. Even if the back-translated English reads awkwardly, that is usually fine as long as the Japanese is natural. Judge by "does it get the intended message across?", not by "is it natural English?"

Consolidate feedback

When revision requests arrive from several departments at headquarters at different times, the production side can't tell what takes priority. Name one point of contact and send feedback all at once, in a single round. Adding the reason for each change (a legal requirement, or a matter of taste) makes it easier for the Japanese team to propose alternatives.

Build the schedule around the time difference

• State review and approval deadlines in both time zones
• So work doesn't stall waiting for a reply, agree on a rule such as "if there's no response by this date, we proceed with this version"
• Keep regular meetings short and schedule them when both sides' working hours overlap

Agree on ad account and footage rights in writing

Rights are where disputes tend to arise later. Settle the following in writing before production begins.

• Who owns the ad accounts and measurement tools (in your name or the partner's), and what happens to them when the contract ends
• Who holds the rights to raw footage and finished videos, and whether they can be used in other countries or on other platforms
• The talent's usage period and scope (platforms, countries, duration), and the terms for extending it
• The license scope for third-party assets such as music and fonts

07✅ Checklist before briefing a production partner

• You have picked out home-market winning and losing creatives, with their metrics
• You have written down a hypothesis for why each one won (or lost)
• You have decided which of the four stages to start from, based on your product and existing footage
• You have listed banned expressions, claims you can't substantiate and past rejections
• Your measurement tool and event (conversion) definitions are set up before ads run
• You have agreed on KPI targets and when you will judge results
• You have settled script back-translation, a single feedback contact and approval deadlines
• Rights to ad accounts, footage and talent are agreed in writing

❓ FAQ

📚 Related articles

📖 Sources

1. Dentsu (電通), 「2025年 日本の広告費」 [2025 Advertising Expenditures in Japan] (announced March 5, 2026) — total ad spend ¥8.0623 trillion; internet ad spend ¥4.0459 trillion, 50.2% share
   www.dentsu.co.jp/news/release/2026/0305-011003.html
2. CyberAgent (サイバーエージェント), 「2025年国内動画広告の市場動向調査」 [2025 Domestic Video Advertising Market Survey] (March 9, 2026) — video ad market ¥885.5 billion (122.2% YoY), of which vertical video ads ¥204.9 billion (155.9% YoY); vertical video forecasts of ¥277.1 billion in 2026 and ¥564.8 billion in 2029
   www.cyberagent.co.jp/news/detail/id=33050
3. Institute for Information and Communications Policy, MIC, 「令和7年度 情報通信メディアの利用時間と情報行動に関する調査報告書」 [FY2025 Survey Report on Usage Time of Information and Communications Media] (June 26, 2026) — YouTube 81.5%, Instagram 54.8%, TikTok 36.7% (ages 13–79); weekday internet use 183.9 minutes vs. real-time TV 156.1 minutes
   www.soumu.go.jp/menu_news/s-news/01iicp01_02000130.html
4. TikTok Japan, "Socio-Economic Impact Report" (June 2026) — about 49.5 million monthly active users in Japan (as of end of May 2026, company figure excluding overlap with TikTok Lite)
   newsroom.tiktok.com/tiktok-socio-economic-impact-report-june-2026?lang=ja-JP
5. Consumer Affairs Agency (消費者庁), stealth marketing notice under the Premiums and Representations Act — effective October 1, 2023; examples of labels that show content is advertising
   www.caa.go.jp/policies/policy/representation/fair_labeling/stealth_marketing/