How does the use of negative keywords with broad match modifiers influence campaign efficiency when the keyword list contains words with multiple meanings in Japanese?

Using negative keywords with broad match modifiers is essential to refine campaign efficiency when a keyword list contains words with multiple meanings in Japanese (homonyms). Japanese has many homonyms that can lead to irrelevant ad impressions if not carefully managed. Broad match modifier (BMM) allows ads to show for searches containing the keyword or close variations, regardless of word order. Negative keywords prevent ads from showing for specific search terms. When negative keywords use BMM, any search query containing those negative keywords, or close variations, will not trigger the ad. This is powerful but must be applied with care. Consider the word 'カメラ' (camera), which can refer to both digital cameras and security cameras. If selling digital cameras, add '-防犯カメラ' (-bouhan camera - security camera) as a negative keyword with BMM. This prevents ads from showing for searches related to security cameras, improving relevance. However, overly broad application of negative keywords using BMM can inadvertently block relevant traffic if the negative keyword shares a meaning with intended keywords. It's crucial to monitor search query reports to identify instances where negative keywords are blocking relevant searches. By combining targeted positive keywords with carefully selected negative keywords (using BMM), ad relevance increases, CTR improves, and wasted ad spend decreases. This method provides effective control where words have many potential meanings. Without this, ads would display for irrelevant queries that waste budget.