m19 Japan: +569% sales for Aster One with automated bid management

Key Takeaways

What this business case illustrates:

• m19 enables significant growth in Amazon ad‑attributed sales, even during a complex product transition.
• Automated bid management and keyword expansion beyond branded terms can generate new demand without increasing advertising costs (ACOS).
• Leveraging retargeting through Sponsored Display helps guide existing customers toward new products while preserving sales of legacy SKUs.
• m19’s automation reduces manual campaign workload and error risk at the ASIN level — a key competitive advantage in mature markets like Japan.

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Aster One is a Japanese cosmetics brand best known for its innovative Kamika cream shampoo. Operating on Amazon Japan since 2012, the company built a loyal customer base with steady performance of its original products. When Aster One prepared to launch an upgraded version of its flagship products, the Japanese brand faced a key challenge: encouraging loyal customers to adopt the new formula while still supporting sales of the existing lineup.

Before this new release, Aster One managed its advertising campaigns on Amazon manually. But to successfully handle a product transition at the ASIN level, manual adjustments quickly became too time-consuming and prone to error. To gain more precision and scale, the brand turned to m19, the AI-powered ad automation platform operated by m19 Japan.

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Our approach

• We first broadened the range of keywords used in Aster One’s campaigns. Previously, the brand focused mostly on branded keywords. With m19, hundreds of new non-brand keyword combinations were automatically created and linked to individual ASINs. Thanks to conversion predictions and daily bid adjustments, m19 expanded targeting opportunities — driving uplifts in both sales and ROAS.
• In parallel, we activated Sponsored Display remarketing: shoppers who had viewed the previous product version were retargeted with ads showcasing the upgraded one. This created a smooth transition path toward the new product while maintaining visibility for the older SKUs.

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Key results (4-month period)

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These results were achieved without increasing overall ACOS, a strong indicator of efficient scaling and optimized spend.

By relying on m19, Aster One successfully transitioned customers to its new product range without cannibalizing existing sales — while significantly improving overall advertising performance.

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👉 Read the full business case on Amazon's website here

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Why This Matters in Japan

Japan’s e‑commerce market is highly competitive, with Amazon Japan often holding ~25 % share of total online retail (by some estimates), driven by high consumer trust and massive traffic. Amazon Japan sees hundreds of millions of monthly visits, making it a critical sales channel for consumer brands seeking scale.

In such a market, automation and precision at scale — especially for keyword management and bid adjustments — become key differentiators in performance.

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In Japan today, e‑commerce continues to grow at a fast pace. The country’s B2C online retail market reached roughly ¥ 27.4 trillion (≈ US$ 245 billion) in 2024.
Amazon Japan remains the undisputed leader among online marketplaces: with around 602 million visits per month (2025 data), it claims a significant share of the online shopping traffic.
Additionally, Amazon Japan is estimated to hold roughly 25% of the total Japanese e‑commerce market — thanks to its vast product selection (hundreds of millions of SKUs), reliable logistics network, and a high level of consumer trust and convenience.

Given this scale and influence, Amazon Japan represents a critical growth channel for any brand targeting Japan. Having a dedicated local partner like m19 Japan — with local knowledge, cultural insights and operational execution capabilities — therefore makes a real difference when launching or relaunching products on the Japanese market.

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When m19 Is Particularly Effective

m19 tends to deliver strong results when:

• High volume of ASINs or product lines needing individualized bidding logic.
• Complex product transitions, like renewal or repositioning of best‑sellers.
• Competitive, non‑brand keyword opportunity exists but is difficult to scale manually.
• Need for reduced manual workload and error risk in ad operations.

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When m19 Might Be Less Suitable

While powerful, m19 may not be the optimal fit in these scenarios:

• Very small catalogues with limited keyword data — AI needs sufficient data to generate predictions.
• Low monthly ad spend — automation delivers most value at scale; if budgets are minimal, manual approaches or simpler tools might suffice.
• Simple brand strategy with negligible non‑brand traffic — limited incremental keyword opportunity.
• Strict budget ceilings without flexibility for bid experimentation — data‑driven automation can be constrained.

These considerations are especially relevant in Japan, where retail competition and keyword dynamics can vary widely by category and audience intent.

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Final Recommendation

For brands navigating product transitions, competitive keyword landscapes, or rapid scaling ambitions on Amazon Japan, m19’s automated bid and keyword management is a high‑impact solution. By reducing manual operational burden and leveraging AI‑driven optimization, brands can accelerate performance without proportional increases in cost or headcount.

If you’re preparing a major product update or want to unlock new non‑brand traffic opportunities in Japan’s Amazon marketplace, using an automation platform like m19 can create predictable, measurable growth — while freeing teams from daily ad micro‑management.

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