PERPANEP German Binding Smooth 4mm Grid Notebook / KOKUYO

• Size: Slim A5
• Inner paper dimensions (H × W): 210 × 135 mm
• Outer dimensions (H × W × D): 222 × 140 × 15 mm
• Ruling: 4mm grid
• Sheets: 96 sheets
• Binding: German binding
• Inner paper: Woodfree paper, Smooth, 96g/m²
• Paper certification: Forest certified
• Note: Pencils and mechanical pencils may produce lighter lines on this surface

PERPANEP is a notebook line built around one idea: matching paper texture to the pen you use. The name itself comes from that premise, and this Smooth variant sits at the slippery end of the spectrum, developed for fountain pens, rollerballs, and gel pens where low friction is everything.

The paper is a proprietary woodfree sheet at 96g/m², chosen not just for weight but for a surface that lets ink settle in a way that shows shading and line variation. It's heavy enough to resist bleed-through, smooth enough that the pen barely registers resistance.

The German binding is the structural choice that ties it all together. Unlike standard case binding, German binding uses a flexible spine that allows the cover to fold back on itself completely. The result is a notebook that lies perfectly flat at any opening, with no raised ridge at the gutter. The 4mm grid is proportioned to support both handwriting and small diagrams without the lines feeling too dominant.