The Japanese suffix '階 (かい)' is used to indicate the floor or level of a building. It is commonly attached to numbers to specify which floor something is on. For example: second floor「二階」(にかい). This suffix is essential for giving directions or describing locations within multi-story buildings. It is important to note that '階' is always used in combination with a number or counter, and it cannot stand alone to mean 'floor'. Additional examples include: third floor「三階」(さんかい), first floor「一階」(いっかい).
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