The battle between the Blue Jays and the Royals turned literary when the Toronto and Kansas City libraries traded good-natured smack-talk on Twitter.

A Kansas City Library digital content specialist said staff first started using books to trash opposing teams when the Royals made it to the 2014 World Series.

"We had a lot of fun engaging with San Francisco's library during the World Series so we thought we would try it again," Liesl Christman told CTV's Canada AM on Friday.

The battle began on Tuesday, when the Jays fell to the Royals 14-2. The Missouri library posted a photo to Twitter of the spines of three books, using the hashtag "#bookspinepoetry."

Book-spine poetry uses the arrangement of book titles to create a poem.

The book spines in the KC photo read, "Canada," "Sorry You Lost," "What Bluebirds Do."

Toronto librarians were quick to respond to the initial insult, working with social media staff to gather titles to send a message to their rival city.

"We've been having a lot of fun with it and the Kansas City staff are very creative so they're keeping us on our toes," Toronto librarian Vickery Bowles said.

The next day, ahead of another Jays-Royals game, the Toronto Public Library struck back. Librarians posted an image of a Jays mug and three books lined up behind it.

The titles spell out: "Warning," "Kansas City," "It Ain't Over Till It's Over."

Kansas City tweeted a single book title in response: "The Heart Does Break: Canadian Writers on Grief and Mourning."

The library used the hashtags "#MaybeWeWentTooFar" and "#LoveYouToronto."

The Jays went on to win the Wednesday game 7-1, prompting the library to send another book-spine message: "The Comeback," "Blue Jays," "Blowout," "The Rivals."

The last book in the pile bore the title "Come Together," a reference to the hashtag used on Twitter by Jays fans.

The battle resumed Thursday, with Kansas City tweeting: "Oh Canada," "Say Goodnight to the Boys in Blue," "Say Hello," "Kansas City Barbeque."

Toronto responded with the help of some strategically placed Jays paraphernalia: "Oh…,""Missouri," "You Are," "Mistaken," "We," "Get the," "Win," "You," "Get the,' "Bacon." 

"We're looking forward to responding fairly soon," Kansas City's Christman said.

Both libraries have seen their photos shared across social media, with thousands of retweets and messages on Facebook.

Bowles said people have stopped Toronto librarians to tell them how much they're enjoying the battle.

"It's really started something that we're all having a lot of fun with and it's a way to support the Blue Jays," she said, adding that she hopes the two libraries will keep it up until the end of the series.

Canada AM joined in the battle after speaking with Christman and Bowles on Friday, tweeting a photo of three books spelling out: "Better Than Before," "Faster, Stronger," "A Flag for Canada."