Claim drafting, independent claim refers to other independent claims

[patentbuddy]

Likely a softball for this audience:

6. A blah apparatus comprising:
   the X according to any one of claims 1 and 5; and
   a Y.

What if an independent claim references multiple other independent claims?  Is this improper?

[DogDayPM 9er9er9er]

Likely a softball for this audience:

6. A blah apparatus comprising:
   the X according to any one of claims 1 and 5; and
   a Y.

What if an independent claim references multiple other independent claims?  Is this improper?

Um, check me if I'm wrong, but by very definition an independent claim does not reference (depend from) other claims.  So it's either improper, or it's a dependent claim masquerading as an indep.

Sometimes particularly with EP practice you'll see claims that appear to be independent but are dependent usage type claims.  For example, independent claim 1 and its dependent claims 2-9 are drawn to a manufacturing apparatus.  Then you'll see claim 10 reciting, "A method for forming widget X, comprising the steps of providing widget precursors, manipulating widget precursors in fashions A, B, and C, performing (insert 4 more process steps), [then finally it gets around to] wherein said later process steps are performed on an apparatus according to any of the preceding claims." 

Claim 10 is a dependent claim.  It could have been made independent by reciting in the last clause "performed on an apparatus comprising ____" (____ = all the elements in the independent claim 1 apparatus).  Then write 8 more dependent claims 11-18 adding the apparatus elements in claims 2-8. 

But in EPO, I think claim 10 (dependent on any of claims 1-9) only counts for fee purposes as 1 claim, not as 9 claims the way it does in the US. 

[JimIvey]

Any claim that requires reading of another claim for its definition is dependent.  It doesn't matter whether the claim begins with "A" or "The".

Regards.

[PatentDave]

What you have there in particular (and you almost state it exactly as such in describing it yourself) is a multiple dependent claim. 

If there is anything which makes your claim "improper," it is your recital of "any one of claims 1 and 5" which might be an improper multiple dependent claim format.  Check the MPEP on that one for proper formats.

But as stated by Jim, any claim which is dependent upon another claim is - by definition - a dependent claim.