Booleanhaku

Booleanhaku refers to the technique of constructing search queries using Boolean logic to control which documents are returned. The approach is based on Boolean algebra, developed by George Boole, and was adapted for information retrieval to express precise inclusion and exclusion criteria.

Core operators typically include AND, OR, and NOT. AND narrows results, OR broadens, and NOT excludes terms. Many systems support phrase searches with quotation marks, grouping with parentheses to specify precedence, and wildcard or truncation symbols such as climate* to match multiple word forms. Some interfaces also offer field qualifiers like author:, title:, site:, or filetype: to constrain the search further.

Example: (renewable AND energy) AND (policy OR regulation) AND NOT subsidy. Phrase search: "climate change". Truncation and field limits can reduce noise and increase recall for exact needs. However, the effectiveness of Booleanhaku depends on the search system's syntax handling and indexing, and overly complex queries can be brittle or miss relevant results.

Booleanhaku remains foundational in databases, libraries, and legal discovery, where precise logic is valued. In many general web searches, natural language processing and ranking algorithms have reduced reliance on explicit operators, but advanced users still employ Boolean queries to control scope and reproducibility.

Related topics include Boolean algebra and information retrieval, as well as advanced search techniques and query languages.