Claims with reference to single dependent claims

Question

I understand that one cannot claim with reference to a multiple dependent claims as set forth in MPEP 608.01(n) Dependent Claims[R-11.2013].

However, can one have claims with reference to a single dependent claim?

In other words:

Claim 1: A gadget comprising .....(independent claim)

Claim 2: A gadget as in claim 1 ..... (dependent claim)

Claim 3: A gadget as in claim 2 ..... (dependent claim)

Does one have to stop here or can one continue as follows:

Claim 4: A gadget as in claim 3 ..... (dependent claim)

Claim 5: A gadget as in claim 4 ..... (dependent claim)

Where is this discussed in MPEP?

Answer 1

Yes, that is permissible and defined in paragraph 6.18. For instance, US 7,756,129 is a grant with 401 claims, although they are not all in serial as in your example. Keep in mind that writing dependent claims in serial creates easy targets for invalidating large numbers of your claims.

¶ 6.18 Series of Singular Dependent Claims

A series of singular dependent claims is permissible in which a dependent claim refers to a preceding claim which, in turn, refers to another preceding claim.

A claim which depends from a dependent claim should not be separated by any claim which does not also depend from said dependent claim. It should be kept in mind that a dependent claim may refer to any preceding independent claim. In general, applicant’s sequence will not be changed. See MPEP § 608.01(n).

During prosecution, the order of claims may change and be in conflict with the requirement that dependent claims refer to a preceding claim. Accordingly, the numbering of dependent claims and the numbers of preceding claims referred to in dependent claims should be carefully checked when claims are renumbered upon allowance.