Kondo opens by introducing her core methodological departure from conventional tidying advice: rather than tidying room by room (which she argues leads to endless, incomplete cycles as items get shuffled between spaces), her KonMari Method organizes by category — clothes, books, papers, and so on — tackled comprehensively, all at once.

Why this approach works better, according to Kondo:

• Tidying by location often means the same category of items (like clothes) gets addressed repeatedly across different rooms, never producing the sense of genuine completion needed to make tidying feel finished
• Gathering every item in a single category together at once — every piece of clothing from every room in the house, for example — reveals the true volume of possessions in a way that's often genuinely surprising and motivating
• Kondo frames tidying as a discrete, completable event rather than an ongoing chore, arguing this reframing is essential to why her method produces lasting change rather than the temporary tidiness that typically fades within weeks

This category-based, all-at-once approach is the structural foundation for the rest of the book's specific guidance.