The origin of poker is still ambiguous. Some historians say poker’s origins can be traced to a domino-card game played by a Chinese emperor in 10th century; others claim it is a descendant of the Persian card game “As Nas,” which dates back to the 16th century. But one thing is clear that no matter when the poker is invented, the cheating cards is shown up in the next minutes.
At first, people usually scrap or bend the cards slightly. Use the nail to scratch the card leaving a rough trace. For this method is in high risk of getting caught, it had been replaced quickly. People start to change the pattern on the back of a card by adding some tiny sections. For example, increasing the petals of rose. Or using the pen to make a line thicker than the others. These changes are lightly. Only the person who alter the cards would spot the markings. There is also a similar way: shading cards. Use a color approximates to the tint of the card to fill a smart pattern of the back, such as circle, triangle and polygon. The right part represents the card suit while the left part represents the card number.
With the latest technological advances used along the way, the invisible ink shows up. It is the most popular way in card marking. Use the invisible ink to write down on the cards. The markings will disappear when the ink gets dried. The most common way to read markings is wearing the infrared contact lenses or glasses. There are some special ink can be detected by infrared camera only. Now, there are various marked playing cards selling on the market. The marks are printed by machine which could be kept for a long time than hand writing. However, a few people still want to create their own marks by using ink pen.
Each methods of cheating card has more or less risk of being found. Knowing the card marking ways above prevents you from being cheated.