Stationery.
paper, esp. that used for writing letters, or writing materials such as pens, pencils, and books for writing in
文房具
筆・ペン・墨・インク・原稿用紙・ノート・定規など、物を書くのに必要な類の品物。文具
Why?
The typical justification you'll often hear for the continued use of pen and paper is that:
"countless studies have shown your brain to be more engaged and increases your focus and productivity."
Fair enough.
But there's something more beyond the modern desire to squeeze every last productive juice out of your brain. There's something... different about seeing a physical record of your thoughts, insignificant or important.