The Auto Response Board (ARB) was the first auto sensory chess computer to be sold to the public. It was released for sale in January 1980; amazingly early in the chess computer timeline for such a sophisticated product. With Dan & Kathe Spracklen’s Sargon 2.5 program the ARB was the top chess computer of its day. It cost £649 in the UK, the equivalent of £2,700 at 2018 prices. Even so the ARB is not a particularly rare machine, certainly not in the USA or Germany. The later Grand Master Series ARB is a little less common. Most ARBs come with the Sargon 2.5 program module in the side slot. A program module in this slot is required to get any response from the ARB.

The other program modules produced, the 3, 3.5 and 4.0-50S modules are much rarer than the Sargon 2.5. In particular the Grand Master Series 3 was a poorly conceived program ‘upgrade’ by John Aker (programmer of the Morphy module for the Modular Game System/Great Game Machine) which got bad reviews and was quickly withdrawn from sale. The 3.5, an upgrade of the 3 incorporating bug fixes, opening book changes, minor level and function changes, appears to have sold even worse, indeed barely at all. By the time that the excellent and reasonably priced Grand Master Series 4.0-50S module was issued in Spring 1984 the chess computer market had largely moved on. The 4.0 contains a Dan & Kathe Spracklen program.

My ARB with 4.0 (also pictured here on Hein Veldhuis’s webpage) is like a piece of well used antique furniture. It oozes quality and is a pleasure to play against. The Sargon 2.5 is much less user friendly. The ARB is normally stored in the huge mountain case you see above. However there is also a purpose made Applied Concepts leather carrying case, which itself is a rarely found accessory.

A combination of the Grand Master Series ARB, Series 3, 3.5 and 4.0 program modules and the leather carrying case all add up to a very rare chess computer package. The more so because the 3.5 program module I have appears to be an early example of those provided to testers and journalists in the hope of more positive reviews. Further testing is needed to tell exactly what program this contains but I believe it is probably the ‘production 3.5’. A further ARB module (seen in the picture below), with no front plate or label, contains only an attract mode program which repeatedly flashes the board and keypad LEDs in a colourful sequence. To complete the module parade in the picture are early and later examples of the Sargon 2.5 program module.