The image-based Chelsea Challenge invites fans to identify a total of 60 players from the past century, all of whom are cryptically represented in a scene depicting the club's home ground at Stamford Bridge.
Many of the players from the current squad are among those dispersed in the scene.
Competitors can submit their guesses online at the microsite, where they are able to enter a series of three prize draws, each with a different respective prize.
After submitting their guess, online players can see if they’re "well wide", have "hit the bar" or scored a "goal".
The three prizes on offer are a £50 online Chelsea Megastore voucher, a Chelsea home shirt signed by the first-team squad, and the top prize of a Samsung Galaxy Tab 3 10.1.
Players can also login to Facebook and Twitter to save their progress or reach out to friends and followers for help using #ChelseaChallenge.
The game and microsite was developed with digital agency as part of a wider fan engagement strategy.
The competition is open for entries until Tuesday 24 December and the winners will be drawn on Friday 27 December.