Japanese rulers that do more than measure: Kyoei's Junkissa Retro Cafe reversible 17cm rulers in Cream Soda and Lemon Squash colorways (double-sided markings, rounded corners that won't scratch your pen case), and Kutsuwa's Mojisashi 18cm reading rulers with a clear window for tracking text, sized to span a B5 notebook. $4.99–$5.99.