Z1 File

What are Z1 files and how to open them

Are you having problems opening a Z1 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 Z1 files.

What is a Z1 file?

A .Z1 file is a Z-Code V1 Adventure For Infocom Z-Machine file.

Z-Code V1 Adventure For Infocom Z-Machine File (.z1) is a "story file" intended for very early interactive fiction games created by Infocom. It holds a complete compiled adventure game in a binary format suited to run on version 1 of the Infocom Z-Machine virtual machine. Users encounter .z1 files when they wish to play older Infocom adventures (especially early builds of Zork I) on interpreters that implement the Z-Machine.

These files are produced by Infocom's compiler (originally called ZIL/Zilch) and are read by Z-Machine interpreters such as Windows Frotz. The interpreter loads the .z1 file, reads its version (which must be 1), then executes the game logic, displays puzzles and text, accepts typed commands, and manages game state as defined in the version 1 specification.

Technical detail: the first byte of the file is the version number "1" identifying the required Z-Machine version; the header includes fields (e.g. at byte offsets such as 0, 4, 6, 8, etc.) for memory layout (dynamic/static/high memory), dictionary location, object table, global variables base and other control data.

How to open Z1 files

We have identified one Z1 opener that is compatible with this specific type of Z1 file.

Programs that open Z-Code V1 Adventure For Infocom Z-Machine files

Last updated: August 14, 2026

Various apps that use files with this extension

These apps are known to open certain types of Z1 files. Remember, different programs may use Z1 files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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