expression
Yours truly, the Store Owner; Store owner, at your service
A formal, somewhat old-fashioned closing phrase used by a shopkeeper in written correspondence or notices, similar to 'Sincerely, the proprietor'.
手紙の最後に「店主敬白」と書いてあった。
At the end of the letter, it read 'Yours truly, the Store Owner'.
A set phrase combining 店主 (store owner) and 敬白 (respectfully yours), a formal epistolary closing.