Low Guard: Chudan
The strongest of lightsaber defenses when employed correctly. It is a low guard that begins with the lightsaber held at a diagonal angle, beginning with the user's waist level and the tip of the blade at the level of the opponent's head.

PROS: easy to parry attacks
CONS: predictable attack (for the opponent)

High Guard: Hasso
The most dangerous of all lightsaber guards, it leaves the user with the smallest defensive surface. By the same token, Hasso is the the starting position for some of the most lethal lightsaber maneuvers. The weapon is gripped vertically with both hands, high (shoulder/neck level), with the emitter held close to the side of the head.

PROS: makes it difficult to launch a proper defense
CONS: strong offensively

Rear Guard
The defender moves the sword over his head and, keeping the emitter pointing down, protects his back. This maneuver is considered difficult due to its main challenge: perfect control over the position of the blade (which, under pressure from the opponent's lightsaber - can impact and injure the defender's back.) The rear guard makes it easy to see in a wide viewing angle (180°) but makes it difficult to launch an attack.

PROS: looks badass - period
CONS: weak for launching a proper attack

Spherical (or Circular) Guard
Circling with the blade in a fan-shaped motion, the defending sword strikes the opponent's sword, forcing it outward. This is the best form of defense against thrusting attacks. The maneuver should be executed with both hands on the hilt, with the non-dominant hand merely controlling the lightsaber's scope of movement.

PROS: great for parrying thrusts
CONS: not so great for mounting an attack following the parry, above (unless executing a thrust, yourself)

Parrying a Cut/Slice
This maneuver is based on offense: the defender uses all his strength to knock out his opponent's weapon outward, as to leave the latter open for the next (incoming) attack.

PROS: strength-dependent
CONS: strength-dependent

The defender withdraws from the enemy's attack by employing agility and speed.

PROS: facilitates easy parry
CONS: possibility of tripping or backing into a dead end/corner, etc.