And he feels there would be no better way to celebrate that anniversary than with a home victory against Everton on Monday.
That result would see City go top of the table, a measure of their progress under Mancini, who replaced Mark Hughes in the run-up to Christmas.
They are on course for a place in the Champions League, having already secured a spot of the Europa League's round of 32 with Aris Salonika their next opponents.
Richards, who skippered the side in the draw with Juventus in midweek, said: "I enjoy playing football but it went a bit sour under Mark Hughes. Not because of him, I only blame myself for that.
"Roberto Mancini has given me a lot of confidence. I'm back in the England team and hopefully I can continue to play well - I was chuffed to be captain against Juventus - I was honoured that he chose me."