The Premium Heart is Tifa's ultimate weapon in Final Fantasy VII. It is obtained in Midgar after returning using a Key to Sector 5. Much like most ultimate weapons, Premium Heart has very high stats, eight linked Materia slots, and a unique mechanic: the weapon deals damage based on the portion of Tifa's Limit gauge that is filled. Premium Heart has a very high damage output, and can be manipulated to deal considerable damage.
Premium Heart, much like Tifa's other weapons, cannot be thrown. It sells for 1 gil.
The Premium Heart can be obtained by returning to Midgar using a Key to Sector 5 (dug up from Bone Village after Cloud and Tifa rejoin the party). Once obtained, the player can return to the store marked "Item Shop" in Wall Market, and access the computer terminal to get the weapon. If the party includes Tifa and Cid, a unique cutscene plays upon doing so.
The maximum Limit Bar Units is 255 regardless of Limit level (the Limit level simply adjusts the rate at which the bar fills). When the bar is full, the weapon does roughly 1-4x its normal damage depending on the Limit level, and would do 1/16 of that damage when the Limit bar is empty. Unlike most weapon damage modifiers, this modifier doesn't solely adjust the weapon's attack power, but the character's final attack power, which includes Tifa's Strength and weapon attack bonus.
Premium Heart deals more damage the fuller Tifa's Limit gauge is, but less than normal damage when it is empty. Although this means the damage is volatile, it has a higher damage output potential than God's Hand when full. Although the weapon is reliant on filling her Limit gauge, using her Limit often against more powerful bosses is desirable, as it can inflict multiple hits in a single turn. Premium Heart also has eight linked Materia slots, the most linked Materia slots of any of Tifa's weapons.
To optimize the use of the weapon, Premium Heart can be manipulated to perform several attacks while the Limit gauge is full without actually using a Limit, or to simply fill Tifa's Limit gauge quicker before using her Limit again. One way of doing this is to pair Cover Materia with several Counter Attack Materia. As these Materia stack, Tifa will have a chance to counter for as many times as she has Counter Attack available; if the Counter Attack is mastered, she will counter once for every Materia she has. This strategy is useful against Ruby Weapon, as it allows her to get in multiple hits against a boss that will always attack her. In other scenarios, pairing this with a mastered Cover will not only cause her to intercept more damage, and thus fill her Limit gauge faster, but will cause her to Counter Attack more frequently.
Inflicting Tifa with Fury can help her gain Limit more often. Using Tifa's Limit frequently is normally desirable, as it can deal vast amounts of multi-hit damage to enemies. In cases where the player wishes to preserve Limits, as an encounter is close to death or too weak to be worth it, the player can make use of Command Materia to attack when her Limit gauge is full. With Steal equipped, Tifa can use the Mug ability to deal a normal physical attack if the player wishes to preserve a Limit to use against a more powerful enemy. As an alternative to this, Added Cut Materia, paired with a basic Command Materia, can also allow her to perform damage normally if the player does not want to use a Limit and would rather preserve it for different encounters.
Premium Heart has four lots of two linked Materia slots. Although this means it is the best weapon for Tifa if she is using Magic Materia or Summon Materia, these are suboptimal for her, and are better given to other characters (except in the case of utility, such as Phoenix paired with Final Attack). Instead, Tifa should use the slots for Independent Materia, such as multiple Counter Attacks, HP Plus, or Mega All. Most Command Materia abilities can also be very useful and can be paired with Support Materia, such as Added Cut and HP Absorb, to take great advantage of her damage. Added Cut can be used effectively with any Command Materia equipped on Premium Heart to optimize Tifa's damage. Command Materia that replace Tifa's basic attack, Slash-All and Double Cut, can be useful in between Limits. Tifa is also a good candidate for the Master Command Materia, particularly paired with Added Cut, as all the abilities are useful for her and can take advantage of her physical damage.
Although Premium Heart requires some manipulating to make the most it, it can deal vast damage even when the Limit gauge is not full. It is thus a formidable weapon for Tifa, though God's Hand can be used in situations where Tifa needs 255% accuracy.
Behind the scenes
It is possible that the Premium Heart's damage formula is bugged, since the "1" value in the way it is written has almost no effect. If the formula was instead : , the weapon would do 1x its normal damage when the Limit bar is empty and up to 5x damage with a full level 4 Limit gauge. The actual formula causes Tifa to do less than normal damage unless her Limit bar is at least 1/4th full at Limit level 4, which many players consider worse than a non-ultimate weapon.