MacRumors tips us off to the fact that Apple has begun advertising the iPhone 5s in various magazines. Up until recently, there hasn't been much advertising in the way of the iPhone 5s. Indeed, most iPhone advertising over the past few weeks has focused on the iPhone 5c with a series of really great and delightful commercials. Apple has also been advertising the iPhone 5c heavily via billboards in large cities like Chicago, San Francisco and New York.
As for the 5s, MacRumors notes that the following ad appears on the back of this week's edition of The New Yorker.