Charge Blade Overview

Charge Blade (チャージアックス Chājiakkusu) is a new weapon first introduced in MH4. This weapon is somewhat similar to the Switch Axe, with the ability to switch between two different weapon modes: the Sword Mode and the Axe Mode. Sword Mode comes with a shield for blocking, is relatively quick, and is primarily used for charging up energy. Once enough has been charged, it can be stored in the shield, and the hunter can use powerful explosive attacks in the slower but stronger Axe Mode. In MH4U, the shield itself can also be charged for a damage bonus, and enables the destructive Super Amped Element Discharge (colloquially referred to as the "Ultra Burst").

- Weapon Traits :

The Charge Blade is well known for its versatility and high skill ceiling, being well applicable to a myriad of situations via its two modes.

Sword Mode

• The weapon is unsheathed in this mode by default.
• Sword Mode is primarily used for building up energy.
• The weapon will automatically block at the end of a Roundslash attack, and at the beginning of a morph-to-axe attack.
• The player can attack with a morph-to-axe attack immediately after blocking.
• Enough attacks will cause the Phial Meter next to the player's Sharpness Meter to glow yellow, then red. Charging the axe (R+A) when this meter is yellow will fill three (3) phials, and charging while red will fill five (5) phials.
• Overfilling the Phial Meter without charging the axe will cause it to display a message that says "CHARGE," and will cause all attacks in sword to bounce regardless of sharpness.
• The easiest way to fill the Phial Meter is to use the charged double-slash attack (Hold A for a moment, then release) and the Roundslash.
• Press R+X to morph to Axe Mode and attack.

Axe Mode

• The player can unsheathe and immediately morph to Axe Mode with R+X+A.
• Axe mode is to be used when the player has charged energy phials.
• Pressing the A button while in Axe Mode will perform attacks that consume these phials, typically one per attack. The player can also press X+A to immediately use the slow but powerful Amped Element Discharge, colloquially known as a "Super Burst." The weapon will automatically morph back to Sword Mode after this attack.
• Charge Blades can have Impact phials, which deal explosive damage and can stun a monster, or Element phials, which deal a heavy dose of the weapon's elemental damage.
• Introduced in MH4U, pressing the R button during the initial "charging" animation of a Super Burst will instead charge the shield and perform a Roundslash, causing the shield to glow red, or making the entire weapon glow red in Axe Mode. This gives a 20% damage bonus and causes shield-bash attacks to deal Phial damage. A charged shield will last 30 seconds per phial consumed, and must be replenished to maintain the damage bonus.
• A charged shield while in Axe Mode grants access to the powerful Ultra Burst attack in place of a Super Burst. The Ultra Burst consumes the shield's charge and all available charged Phials in exchange for a powerful shockwave attack. Be sure not to miss! If you wish to use the Super Burst instead and keep your shield's charge, hold BACK on the analog stick (that is, the opposite direction your character is facing relative to the camera) and press X during the "charge" animation before the Burst.

- Pros and Cons :

Pros

• Good Defensive and Offensive capability
• Several infinite combo
• Transition between two modes can link a combo
• After Charging the shield, its defense capability is as good as lance and gunlance
• Can stun monster with Power phial and Element phial exploit elemental weakness for massive damage
• Good dps from sword mode and have incredible range in axe mode 

Cons

• Long animation attack from its ultimate attack ( Ultra Burst)
• Slower than SnS in sword and shield mode
• Ultra Burst can disrupt other player
• Need timing for landing Ultra Burst safely
• You need master BOTH modes in order to reach the weapon maximum ability
• Long sheath animation

- Tutorial for Beginner Hunter (by GaijinHunter)

https://www.youtube.com/watch?v=t5wRRvB-41I