Tomorrow's World: Mobile Phone 13 September 1979 - BBC

It's debatable if this is AI but basically it looks at all the moves you can make then all the responses an opponent can make and then what you can do back etc. and attaches scores based on pieces taken and the positions. And then goes with the best score. Conventional chess programs use a similar algorithm and ones like AlphaZero are similar except they use machine learning and neural nets to judge how good positions are rather than a simple point score system. I remember trying to write a similar one after seeing the algorithm explained on the TV show Tomorrow's World, around 1980. (Here they are explaining the cutting edge of mobile phones in the day [this video] )