Introduced in 1918. This is one of four extremely rare World War I back designs that were part of the War Series. They were only issued for one year and their rarity suggests that they were never actually released to the public, perhaps because the war ended that same year. Only a handful of complete decks are known to exist today. The other three designs are Big Gun, Flying Ace and Invincible.

The box art is substituted for the red back, above, until I scan a red single from a 1917 salesman's sample book. Pictured below is an Andrew Dougherty deck with a similar theme to the very handsome ace of spades.

  25. Diamond Plaid                                            27. Eagle