Japanese coffee can be written in katakana as コーヒー or with the characters 珈琲. The source explores the historical and cultural associations of those forms, including the account connecting the character choice with Udagawa Yōan. The difference is linguistic and stylistic, not a classification of beans or brewing methods.
On a café sign, 珈琲 may contribute to a traditional or nostalgic impression, especially in the setting of a kissaten. That impression does not establish that every such business follows the same roasting or service practice. Read the actual menu and observe the individual café rather than deciding from the lettering alone.
For coffee enthusiasts, the writing offers an entry into the way a drink becomes part of local culture. Compare the cups, spaces and service conventions that accompany it, while separating historical explanation from romantic assumptions. A name can invite curiosity without supplying a complete account of the coffee being served.

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