Follow Via Appia outside Rome, pass through Albano town, cross the first Ariccia's bridge, and after the main square turn on the left and then the first on the right.
You can easily see the Osteria n. 1 from the little square.
From Genzano :
Follow direction to Ariccia on Via Appia, cross the first bridge you will meet and at the end of this one turn on the right and the the first on the right.
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