What is ‘Liner’?
In poker games, a Liner is a term for a face card, because when the face card is down and the lower right corner is lifted, a line is visible.
The cards four through ten are detected in much the same way, except you can see spots in the corner, hence the term spotter. Cards without these distinguishing marks are called no-spotter, which have no spots in the corner. There are some poker players who use this information to based their decision on whether to place a bet. There are some who argue this is a form of cheating, because this gives them an unfair advantage over their opponent.
Liner, Spotter, and No-Spotter cards are not intentionally marked cards, however there are many ways in which poker cards are marked, and have been throughout the history of poker.
Marking cards, or altering cards, is a method only known to the player marking them, and for the marks to be effective, they must be seen on the back of the playing cards. In a game of poker, it doesn’t matter who shuffles the cards or deals them in order to use the cards that are marked.
Historically speaking, marking cards involved bending the cards or crimping them. Tiny pinpricks known as ‘blisters’ were also used. When card designs first started appearing on the backs of the cards, cheats started altering them with various inks and pigments to add or remove lines from the back of the design. Other ways of card marking involve block-out, scroll, shade, and tint processing.
Block Out: This process is done by using ink the same color as the back of the card and changing the design slightly. For example, changing the petals or blocking out part of the design.
Tinting: This process is a subtle variation of block-out where certain areas on card backs are marked by lightly tinting certain details.
Cut-Out: This process involves scraping off part of the design with a razor.
To gain an advantage in the game, it is not even necessary to mark all the cards, even marking one specific rank is enough to gain an advantage against an opponent, however this underhanded way of playing is certainly not recommended.