BJK File

What are BJK files and how to open them

Are you having problems opening a BJK file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BJK files.

What is a BJK file?

A .BJK file is an OpenMG BeatJam Skin file.

OpenMG BeatJam Skin is a format used by the BeatJam music software by JustSystem to skin or theme the user interface, letting users change the look of BeatJam's player and display screens. It stores resources like graphics, layouts, icons, colors and perhaps control positioning so that skins are swapped in without changing the program's core.

BeatJam software creates these skin files, which it then reads to present alternate visual designs in its menus, mini-player, and main display. Typically a skin file contains multiple bitmap graphic images (for buttons, backgrounds, etc.), an XML layout or settings file that tells BeatJam where and how to use those graphics, and data about repetition or tiling of textures, control elements, and possibly transparency.

This format is packaged as an archive container (essentially a compressed file) that holds the graphics and configuration files. The archive begins with the ZIP signature PK 0x03 0x04 at the very start. Inside are image files with names or tags like "N.BMPUT", "T.BMPUT", "SE.BMPUT", a layout or config file called "SKIN.XMLUT", and other identifiers such as the keyword "REPEAT".

How to open BJK files

Important: Different programs may use files with the BJK file extension for different purposes, so unless you are sure which format your BJK file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 24, 2026

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