dōjin, literally "same person" and shi is a contraction that means magazine. Dojinshi works are usually amateur works; however, they are sometimes made by professionals too. Doijunshis' are made like an extension of the original manga, hentai, or videogame. They contain the same characters, and usually the same setting, but what they do is they explore the plot or a certain characteristic more in deep, or they just extend the story to whatever the new creator thinks it should go. They are usually self-publish, so the creator has the liberty to take as much time, and effort as he or she wants. They sound like the OVA, but they different. OVA is based in manga, and they try to change the story, but Dojinshi works can go to wherever the new author wants it to go. They have Dojinshi conventions as well. An intersting aspect of this trend is the copyright. One would think that people can get in trouble for explictly copying someones elses ideas, but the truth if far from that. Many many times they are actually encourage by the original authors. Why? well first there is a chance that people get to know the original the manga from the doijinshi, and second the artits can get fresh ideas from them.