While the third shirt is an 80s/90s concept, that’s not to say that teams were forced to come up with emergency alternatives before then, as Arsenal experienced at Blackpool twice in 1970.
As they had a red and white home kit and yellow away, Blackpool’s tangerine had the potential to clash with both. When Arsenal had to go to Bloomfield Road in the 1970 FA Cup, they wore plain white shirt (possibly the early 60s away) with the away blue shorts and red socks.
Then, with Blackpool having been promoted to Division 1 for the 1970-71 season, for the league game at Bloomfield Road in November, Arsenal resurrected the navy away kit which had been worn for two seasons until 1968.
Navy kits had actually been banned because of their similarity to referees’ outfits, and Arsenal had to get special permission to wear that strip. Should they have developed something new?
A trope I like is when the away and third shirts are reversals of each other, and doing this would have worked well for Arsenal, I feel.