Most Difficult Bach Piece

[nanabush]

I've played quite a few Bach pieces, some inventions, p/f's and the Italian Concerto but wanna know what you would consider his most difficult piece for piano.

[phil13]

Same one that Bach himself considered the hardest- the Goldberg Variations.

Phil

[pianote]

i second that

[steveie986]

Goldberg Variations and the Art of the Fugue, though the latter, of course, wasn't specifically written for the keyboard. There are also many devilishly difficult fugues from the WTC.

[soliloquy]

As far as like, density is concerned, some of the Overtures and the Chromatic Fantasia & Fugue BWV903/948 are the hardest, but aren't really long enough to contend with Goldberg Variations.

[bartolomeo_]

While realizing that the original poster asked about piano works in particular, I would point out that many of Bach's most demanding keyboard works were written for organ.  Among larger-scale works, the trio sonatas and the "Wedge" prelude and fugue are among the most difficult.