Writing sheet for touch panel pen, touch panel, touch panel system, display device, and method for selecting writing sheet for touch panel pen

It is intended to provide a writing sheet for a touch panel pen which can offer favorable writing feeling. The present invention provides a writing sheet for a touch panel pen (A) given below, the writing sheet having a surface whose maximum peak height Rp of a roughness curve and maximum valley depth Rv of the roughness curve defined in JIS B0601: 2001 satisfy the following conditions (A1) and (A2), and whose average wavelength λa calculated according to the following expression (i) from average tilt angle θa and arithmetic average roughness Ra defined in JIS B0601: 2001 satisfies the following condition (A3): 2.0 μm≤Rp≤8.0 μm (A1), 0.8 μm≤Rv≤6.0 μm (A2), 45 μm≤λa≤300 μm (A3), and λa=2π×(Ra/tan(θa)) (i), the touch panel pen having an angled part in at least a portion of a tip region, wherein a volumetric change of the tip region upon application of a vertical load of 100 gf is 1.0% or less.