I have been given the task of checking the most recent patents of our competitors for infringement. I must say I am not a specialist in patents but I mostly enjoy the learning experience.

One of our competitors has changed the structure of independent claims in recent years.

In the past, they used to briefly describe the device and new elements followed certain keywords, such as "wherein..." in English and "dadurch gekennzeichnet..." or "wobei..." in German. This made it easy for a non-specialist to understand what is claimed.

In the new structure the device is described in more detail in the claim, containing the description of the various combined elements and their function/characteristics/positions, while the innovation is buried somewhere in there, i.e. no keywords are used now. Example: "A device A with characteristics G to perform function K; a plurality of elements B with characteristics/positions H for function L; a plurality of elements C with characteristics/positions I for function M; ..."

I am just having a bit of trouble explaining to my boss "what exactly is patented". We can see what is novel but I do not know if this is what is truly claimed. If I understand correctly:

  • the claim concerns the combination of the different elements, regardless of what is new and what is old - everything must exist for a patent to be infringed;
  • it is the reader's / the examiner's job to figure out where the novelty lies

Could you please comment on the correctness of my interpretation? Is there an advantage for this structure in comparison to the previous one?

I hope my question is understandable and I apologise for my oversimplified examples.

(Edited for readability)

1 Answer 1


What you are describing is essentially the difference between two philosophies of patent claiming: an Anglo-Saxon one and a Germanic one.

More formally, there are two styles of claims:

  1. one-part form (the usual form in the US and UK-derived jurisdictions); and
  2. two-part form (the usual form in Europe).

Two-part form

Two-part form (also called German-style claiming or a Jepson claim) is where the known portion of the claim is separated from the novel portion by a particular phrase.

This is particularly wide-spread in Europe, where it is mandatory. That is, EPC r 43(1) provides that claims shall contain:

(a) a statement indicating the designation of the subject-matter of the invention and those technical features which are necessary for the definition of the claimed subject-matter but which, in combination, form part of the prior art;

(b) a characterising portion, beginning with the expression "characterised in that" or "characterised by" and specifying the technical features for which, in combination with the features stated under sub-paragraph (a), protection is sought.

The magic words are "dadurch gekennzeichnet" or "gekennzeichnet durch" in German and "caractérisé en" or "caractérisé par" in French.

So an example two-part form claim would be:

A system comprising:

a known first widget; and

a known second widget;

characterised in that:

the second widget is placed on the first widget in a novel way.

In the US, 37 CFR 1.75(e) actually mandates two-part form, using the phrase "wherein the improvement comprises". However, as a practical matter, everybody ignores this rule.

One-part form

Any claim that is not in two-part form is in one-part form. In a one-part form claim, the novel features are intermixed with the known features.

So an example one-part form claim would be:

A system comprising:

a known first widget; and

a known second widget placed on the first widget in a novel way.

Advantages of two-part form

The idea behind two-part form is that it allows the reader to easily determine what the applicant thinks is novel. This can lead to the examination process being more targetted on the improvement, and therefore potentially higher quality.

Disadvantages of two-part form (or advantages of one-part form)

Some claims do not lend themselves to two-part form easily. This would be most notable in a method claim, if the novel bit is in the middle. Two-part form would lead to the method steps being presented out-of-order (or at least to some awkward circumlocution).

But even where you could use two-part form: why would you want a reader to know what you think is novel? This just makes your competitor's job easier, for negligible personal benefit.

This latter point is particularly striking in the US, where the preamble is treated as admitted prior art. If you get it wrong, there can be some pretty dire consequences. This is one of the key reasons why, despite the mandate in the rules, few US drafters would use a Jepson claim. In contrast, in Europe the preamble is not binding, and is just treated as a hint to the reader. If you get it wrong, the consequences are mild.

You are perhaps seeing this effect in real life: while the earlier claims in two-part form are easy to understand, the later claims in one-part form require much more work, and even then are somewhat uncertain — surely exactly how you want your competitors to be.


The format of the claim has no bearing on whether the claim is infringed. In either case, an infringer must perform all elements of the claim for it to be infringed, even those elements which are in the preamble of a two-part claim.


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