In the 1970s, one could play correspondence chess in a PLATO System program called 'chess3'. Several users used chess3 regularly; often a particular user would make several moves per day, sometimes with several games simultaneously in progress. In theory one could use chess3 to play a complete game of chess in one sitting, but chess3 was not usually used this way. PLATO was not connected to Internet predecessor ARPANET in any way that allowed mass use by the public, and consequently, chess3 was and still is relatively unknown to the public.