Do couplets read from left to right or right to left

According to the practice since ancient times, the couplets are read in the same way as ancient texts, from right to left, so generally the right side is the first line and the left side is the second line. This is the most common and most formal way to distinguish between the upper and lower lines of the Spring Festival couplet, because the Spring Festival couplet is absolutely pay attention to the "level and oblique". If the last word of a couplet is pronounced in an oblique tone (the third or fourth tone in pinyin), it is usually the first couplet, and if it is pronounced in a flat tone (the first or second tone in pinyin), it is the second couplet.