It was first called "Word Links", but the word "doublets" was in use from the first. It consists in connecting two doublets (words with the same number of letters, usually 3, 4, or 5) by links in which each word differs from the preceding one by one single letter only, as HEAD, heal, teal, tell, tall, TAIL. The chain in which there are fewest links gains the highest marks. The game became very popular in private circles.