In the world of "Bleach," it is difficult to definitively determine which Zanpakuto is the strongest, as the power and abilities of Zanpakuto can vary greatly depending on the wielder and their compatibility with their spirit.

Zanpakuto in "Bleach" are unique manifestations of a Soul Reaper's spiritual power and reflect the individual characteristics and abilities of their wielders. Each Zanpakuto has its own unique name, release command, and abilities. The strength of a Zanpakuto is often linked to the power and skill of the wielder, as well as the level of mastery they have attained.

Zangetsu, as Ichigo Kurosaki's Zanpakuto spirit, is certainly one of the most powerful and iconic Zanpakuto in the series. Its abilities, such as the Getsuga Tensho and various forms of Bankai, grant Ichigo formidable combat capabilities. However, other Zanpakuto in the series possess their own distinct powers and have been shown to be equally formidable.

Some notable examples of powerful Zanpakuto include Kyoka Suigetsu (Aizen's Zanpakuto), Senbonzakura (Byakuya's Zanpakuto), and Suzumebachi (Soi Fon's Zanpakuto), among others. Each of these Zanpakuto has unique abilities and has demonstrated impressive feats of strength and skill in battle.

Ultimately, the concept of the "strongest" Zanpakuto is subjective and depends on various factors such as the wielder's skill, compatibility, and the specific circumstances of a given situation or story arc.