Image reproduced by kind permission, Director GCHQ

Virtual Turing-Welchman Bombe

A 3D simulation of the Turing-Welchman Bombe machine

Find Out More Run Virtual Bombe

What is the Turing-Welchman Bombe?

The Turing-Welchman Bombe was an electro-mechanical device used at Bletchley Park and its outstations during World War II to assist in breaking the Enigma cipher used by the German military.

Based on ideas from a device known as a bomba, designed in Poland by Marian Rejewski as early as 1939, the Turing-Welchman Bombe enabled Bletchley Park to find the daily keys of the Engima machine on a regular basis throughout most of the war.

The British Bombe was designed by Alan Turing with important additions by Gordon Welchman. They were built by the British Tabulating Machine Company in Letchworth, Hertfordshire.

Virtual Bombe is a 3d Turing-Welchman Bombe simulation which can run using just your browser. No install is necessary.

Requires recent internet browser, Google Chrome is highly recommended. For Mac, please use Chrome or Firefox (Safari does not have the required 3d webgl engine yet).

Image reproduced by kind permission, Director GCHQ
What does it do?
Credits and Links


A number of people I need to say thanks and tip my hat to... .. The National Museum of Computing where my obsession was sparked! Make sure you find time to see their rebuilt and fully working Bombe and Enigma demonstrations at the museum but also so much more including Colossus and the galleries on the breaking of Lorenz, the WITCH & EDSAC, Elliott 308 and all manner of home computers you can use. If you are interested in code breaking or WW2, this place has to be on your must visit list. An amazing experience!

3D software

A couple of amazing (and free to use) tools which enabled me to write Virtual Bombe

three.js is a cross-browser JavaScript library for creating 3D computer graphics in a web browser and an amazing piece of work. A big thank you to Mr.Doob for creating this wonder! a free and open source 3D creation suite which was used to create the models.


Creative Commons Licence
Virtual Bombe by is licensed under a Creative Commons Attribution 4.0 International License.

Please feel free to use Virtual Bombe to learn or teach others about the Bombe machine and the work done at Bletchley Park. If you find it useful or if you have any feedback or ideas for making it easier to use or understand, please do let me know.

It takes a long time to research and build these simulations and I love to hear about them being used, whether for your own information or in a classroom for STEM. Do please drop me a line to let me know if you do!

Let me know what you think!

Have I got something wrong, it doesn't work quite correctly on your computer or maybe you just want to say hi - find me on Twitter(X) or check my Facebook pages

Martin Gillow