Dedicated Chess Computers

ChessEval Journal
About Dedicated Chess Computers

The MM-V Machine at the World Championschip, Portorose, 1989

Written by Hans van Mierlo
First edited | 02/09/2014 | by MMO
Last edited | 10/20/2015 |
Additional Information: photos by Hans van Mierlo;
Reference to cite: Mierlo H, The MM-V Machine at the World Championschip Portorose 1989, ChessEval Journal, 3, February 2014,


At the end of 2012, I met Ed Schroder at our User Tournament in Leiden.

had a conversation about the Dutch Computer Association better known as CSVN.
He told me he had several old dedicated chess computers and more.
We agreed that he would send me a list, and he did
There was so many exotic chess computers available, that he decided to make a
open bidding on it.
He published it on his Rebel Homepage and allowed people to bid on these items.

History of the MM-V

Ed Schroder bought the Turbo Kit TK20 from Schaetzle+Bsteh because he did not get the Hardware he wanted from H&G (Mephisto).
Richard Lang got the top class hardware, Ed Schroder the middleclass and Frans Morsh the lower class hardware.
In order to have a chance at the World Championship, Ed needed this Turbo Kit TK20.
The funniest part was that earlier the MM-IV was put out of the Swedish SSDF list on the demand of Hegener and Glaser.
Because the 68020 Almeria from Lang was at that time the Number One of the list, when the MM-IV 16-18MHz was rated, it came on top position above the 68020 Almeria. That was a disaster for Hegener and Glaser and for commercial reasons the SDFF put the MM-IV out of the list.
The reason was simple: H&G sent for free computers to the SSDF for testing. If the MM-IV Turbo were in the list, it would not have been anymore chess computers from H&G.

The story of Hans van Mierlo

I shall write about some more interesting computers/modules later, but presently I would like to present the story of the World Machine MM-V Turbo Kit.

Since a long time, I wanted a  Turbo Kit TK20 from Schaetzle and Bsteh (for more details, see

The Turbo Kit runs at 16 MHz, and in that time, you had to pay 1800 Gulden, even 2000 Gulden for the 18 MHz (around 815 Euro for the 16MHz)... a lot of money...

I succeeded to have one and I went to take it at Ed Schroder's home. Around a cup of tea, we talked about chess computers and more particularly about the MM-V Turbo Kit. The master himself was telling me how things happened.

My meeting with Ed Schroder

This MM V is running... I cannot believe it after all those years passed unused in a cupboard, Ed Schroder told me.

And, he followed asking me if I was knowing that this computer was participating to the WCC of 1989 in Portorose " (see

I was not knowing that....

Then, Ed Schroder started to tell me what was happening and first, he detailed for me the characteristics of this computer.

He told me that this MM-V Turbo Kit had special options:

1- a book made by Jeroen Noomen: the computer open with white only with d4 and with black against e4-d4-c4-Nf3, only c6. These openings are very good and the MM V do react very well on these openings.

2- when the computer starts, it displays CHES and not PLAY

3- The function BDis useful, if power is lost of any reason, it is possible to give the number of moves it has to play and the time available for it. This means when on move 28, the power is lost and we have still 1 hour thinking time left, we could give in 12 moves for 60 minutes. If not and we select the normal level 40 moves in two hours, the computer will play too fast... and on a WCC, that can make the difference between winning or losing.

4- SL3 allows to change the Selectivity of the program. Normal level is on SEL 3. With 5 or 6, the computer will go much deeper in next positions. It could result in a big advantage.

 5- SP0: Ed Schroder didn't remember this option and what it was supposed to do. Maybe, it has to do with Speed?

All this options were not included in the commercial released of the MM-V Modules.


I was completely surprised and also... so happy to get this computer!

At the WMCCC, the program name that was used with this computer was REBEL, but, in many Magazines, the reporters were mistaken and were naming it Polgar (for the reason Polgar was released by Mephisto before the WMCCC 1989).
Well, Ed said, because I didn't get the hardware I needed from H&G, the only way for me in the program was to strip the Evaluation, that was the only way to progress in the Elo rating. Moreover, the MM-V has a special checkmate search that the Polgar doesn't have, but to be honest, i think the Polgar is a better program.


How strong is this MM-V associated with the Turbo Kit?

I estimate the rating being between 2150 to 2200 Elo.

During the WMCCC, this MM-V machine was playing equal against the Mephisto World Machine (WM) Portorose 36mhz 2MB: the Mephisto WM has a rating of 2271.


In conclusion

For my part, I am glad that I was able to add this computer to my Collection and to know the history/story of this Computer

The flat cable was a bit worn off and I replaced it with a new one.

The computer is still fully working and I continue to enjoy it...