the basics 0.1

leave or defensive:

The leave. Note the batsman's head focussed on where the ball had bounced. The bat and hands are held well out of the way of the ball.

The leave is sometimes considered a cricket shot, even though the batsman physically does not play at or interfere with the ball as it passes him. The leave is likely to be used by batsmen during the first few balls they receive, to give themselves time to judge the conditions of the pitch and the bowling before attempting to play a shot. Leaving a delivery is a matter of judgement and technique. The batsman still has to watch the ball closely to ensure that it will not hit him or the wicket; he also has to ensure that his bat and hands are kept out of the path of the ball so that it cannot make accidental contact and possibly lead to him be caught.

A block stroke is usually a purely defensive stroke designed to stop the ball from hitting the wicket or the batsman's body. This shot has no strength behind it and is usually played with a light or "soft" bottom-hand grip and merely stops the ball moving towards the wicket. A block played on the front foot is known as a forward defensive, while that played on the back foot is known as a backward defensive. The application of these strokes may be used to score runs, by manipulating the block to move the ball into vacant portions of the infield, in which case a block becomes a "push". Pushing the ball is one of the more common ways batters manipulate the strike.

for better examples have a look at the above video :)

Take look at RAHUL DRAVID whose defense earned him the name 'THE WALL' from his teamates:

perfect back foot and front foot defense by Rahul Dravid.

 

Talking about how to leave a ball take a look at this:

 TRIVIA:

1) Rahul Dravid became the first batsman to score a century in every test playing nation.

2) His record of 93 consecutive Tests for india is the fifth highest overall and the second highest for an Indian behind Sunil Gavaskar.

3) Dravid has featured in 100-run partnerships over 80 times with 18 different teammates, a record highest.

4) With 461 runs, he finished as the top-scorer in the 1999 Cricket World cup.

5) “Jammy” became the first Indian to score back-to-back centuries in a World Cup.