week5:Rule

   Today, I will explain the rules of American football. Rules of American football is a very complex and detailed, this time I will explain the main rules.

1. How to score
    As I said week1, There are three ways to score.

    1) A player enters the end zone with the ball.
    2) A players catches the ball in the end zone.
    3) A players kick the ball, and passing the ball between the poles in the end zone.
    4) A players tackle to opponents in opponent's end zone.(safety)

    1) and 2) is called "touch down", and they worth six points. Following a touchdown, the scoring team has the chance to score more points through a try, a single opportunity to score points. If scored by kicking, the team gets one point. If scored by what would normally be a touchdown, they get two points.
   3) is called "field goal", which worth three points.
   4) is called "safety", which worth two points.

2. How to advance the ball
    There are three ways.
  1) Running with the ball.
  2) Catching the ball thrown by quaterback.
  3) Kicking the ball.(punt)

   1) and 2) is main ways that the offense can advance the ball, running and passing. Usually, the play begins with the snap. the snap is the motion that the center passes the ball backwards and under his legs to the quarterback. the quarterback then either hands the ball off to a running back, throws the ball to receiver or runs with the ball himself. Once the player with the ball is tackled or goes out of bounds, or a pass hits the ground without a player having caught it, the play is over.
   
     A series of four plays are given to the offense side team. This series is called "down". If the offense advances 10 or more yards in the four downs, they are given a new set of four downs. If they fail to advance 10 yards, possession of the ball is turned over to the defense. 
 Then, the offence team plays "punt kick". punt kick is the play which advances the ball further instead of relinquishing the wright of offence.

3. Foul
  I will show the part of foul. If the team has foul, it is given a penalty. Most penalties result in moving the football toward the offending team's end zone, usually either 5, 10, or 15 yards, depending on the penalty.

・ Holding
   this foul is that a player obstructing opponent's movement by grabbing the opponent players. Penalty yardage is 10.

・ False start
   An offensive player illegally moves after lining up for, or but prior to the snap. Since the ball is dead, the down does not begin. Penalty yardage is 5.

・ Chop block
　An offensive player tries to cut block a defensive player that is already being blocked by another offensive player. This foul is very dangerous for the opponent. Penalty yardage is 15.

・Face mask
  This foul is grasping the face mask of another player while attempting to block or tackle him. Penalty yardage is 15.

・Spearing
Tackling or contacting an opponent with one's helmet. This foul is very dangerous because tackler has the risk of neck injuries.