* ~ Japanese high schools run from grades 10-12.  So there are only freshmen, sophmores, and seniors.
** ~ according to an interview in Shonen Jump with Takahashi-sama, Yugi's father is alive.  He is away on business trips most of the time (like Hanasaki's father) which is why he is never seen in either the manga or anime series.

Small, gentle, and shy by nature, Yugi found it much easier to bury himself in his games than attempt to reach out and interact with others.  Not that he wouldn't have welcomed the chance to share and play with others, he just didn't have the nerve to ask.  Yugi has a very strong sense of wrong and right.  But not so strong as to be overly moralistic, he is a normal, hormone-driven, teenage boy after all.  Though he is incredibly smart and has an amazing talent at games(he almost never loses), his grades don't reflect it, since he tends to play his games rather than study.  After an incident with a school bully earns him the friendship of one Jonouchi Katsuya and later Honda Hiroto, Yugi's life takes a turn for the better.  These two, along with his childhood friend, Mazaki Anzu prove to be true friends.  Sticking by his side throughout all the weird and dangerous events that seem to follow him and his Sennen Puzzle. The Puzzle itself was a gift from his grandfather.  It was given to Yugi when he was eight to eventually be a memento of his Grandpa and it took Yugi eight frustrating years to finish it.  With it's completion came a strange "dark side" to Yugi.  Causing the gentle teen to black out in times of danger and leaving other's to wonder just what has come over Yugi.   If their minds remain intact.

Note:  A large portion of this summary was taken from my Yugi shrine:  Hikari no Tenshi.