Translation guide
A container for holding pencils, pens, and other stationery. In Japanese, the most common word is 筆箱 (fudebako), but other terms exist depending on shape and material.
A box or case for holding pencils and pens, typically used by students.
The most common and general word for pencil case. Literally 'brush box', but used for any pencil case.
I forgot my pencil case.
I bought a new pencil case.
Loanword from English 'pen case'. Common and understood, but slightly less traditional than 筆箱.
There are many pens in the pen case.
Literally 'brush holder'. Less common than 筆箱, but still used, especially for traditional brush cases or soft pouches.
I put the pencil case on the desk.
A fabric or soft case, often with a zipper, for holding pens and pencils.
A rigid, often plastic or metal, box for stationery.
Both are widely used. 筆箱 is the traditional word and very common among school children. ペンケース is a loanword and often implies a softer, zippered case, but can be used generally. In everyday conversation, either is fine.
I take my pencil case to school.
I put the pen case in my bag.
この筆箱は柔らかい。
This pencil case is soft.