Jepson Claims

by Dennis Crouch

The chart above presents the powerful trend in the use of Jepson claim language in US patents over the years. It shows a clear decline in the percentage of patents that include Jepson claim language from 1980 to the present. In the early 1980s, around 8% of patents included at least one claim in Jepson format.  That figure has steadily decreased over the decades, falling to near 0% in recent years.

The Jepson format is a way of writing patent claims where the preamble states the known prior art, and the body specifies the improvements made over this prior art. Typically, the transition phrase will be in the form “wherein the improvement comprises” or “the improvement comprising.”  100+ years ago, patentees were looking for ways to claim an improved device without being directly bound to all the old elements in the device that they hadn’t changed.  They so began putting the known elements into the (substantially) non-limiting preamble and kept the new portions in the body.  The patent office liked this form because to allowed claims that fully embodied the product, not just the disembodied improvement.  In addition, the form facilitated examination because it particularly points out the inventive portions. Ex parte Jepson, 1917 C.D. 62, 243 O.G. 526.

The PTO liked this approach so much that it eventually determined that Jepson claims are the preferred approach.  The patent regulations indicate that any “improvement” invention should be drafted in Jepson format.

Where the nature of the case admits, as in the case of an improvement, any independent claim should contain in the following order: (1) A preamble comprising a general description of all the elements or steps of the claimed combination which are conventional or known, (2) A phrase such as “wherein the improvement comprises,” and (3) Those elements, steps and/or relationships which constitute that portion of the claimed combination which the applicant considers as the new or improved portion.

37 CFR § 1.75.

As the chart above shows, this “should” requirement is obviously not being enforced or followed.  “Should” is a middle ground between “shall” and “may” and indicates to me an obligation on the attorney’s part to actually consider whether “the nature of the case admits” such a claim form.  I expect that many U.S. practitioners have pushed the other way and rewritten similar styled claims from European practice when filing the US case.

I previously wrote:

Jespon claims are so nice to read because they actually spell out what has been improved by the invention.  Unfortunately, they also are seen as increasing the chance that the patent will be both narrowly interpreted and found invalid – and that the statement regarding the prior art will be seen as an admission.  For much these same reasons, most patents no longer particularly identify their “invention” beyond stating that it is embodied by each claim taken as a whole.  Prof. Kayton, who trained generations of patent attorneys in his PRG classes was particularly adamant about avoiding Jepson claims.

Gene Quinn on his blog writes “No patent attorney in their right mind would follow this suggestion.” (referring to Rule 1.75(e)).

Crouch, Jepson Claims (Part II), Patently-O (September 2017). Janice Mueller has written that “A long Jepson-format preamble only furthers the impression [to judges and juries] that the claimed subject matter is merely a minor addition to old technology rather than a pioneering advance entitled to broad protection.” The MPEP further explains that “drafting a claim in Jepson format is taken as an implied admission that the subject matter of the preamble is the prior art work of another.” MPEP 2129. Although the text goes on to explain that the admission does not hold if applicant explains that it is not making an admission or if some other justification is provided.

Back in 2017 when I last wrote about Jepson claims, patent attorneys were still coming to grips with the new law of eligibility and the notion that particularly pointing out the technical improvement over the prior art can be a useful strategy in patent drafting and prosecution.  Judge Lourie though seems to have already recognized this.  He explained in his opinion denying en banc review in the Ariosa case that

The claim to this invention, then, might have been better drafted as a so-called Jepson claim, which recites what is in the prior art and what is the improvement. Such a claim might read, perhaps with more details added: “In a method of performing a prenatal diagnosis using techniques of fractionation and amplification, the improvement consisting of using the non-cellular fraction of a maternal blood sample.

Ariosa Diagnostics, Inc. v. Sequenom, Inc., 809 F.3d 1282, 1286 (Fed. Cir. 2015) (concurring opinion by Judge Lourie); See also Ex parte Jepson, 1917 C.D. 62, 243 O.G. 526.

Jepson Formats and Means Limitations Under More Fire

The MPF Resurrection: Still Waiting for a Miracle?


57 thoughts on “Jepson Claims

    1. 12.2

      Congressional Repu-K.K.K.-es will tolerate the worst behavior imaginable right up to the point where it affects them personally. Try to imagine how depraved these people are who waited until now to get rid of such an obviously toxic criminal slimeball as Santos (assuming that’s his real name). And still many of them voted to NOT expel him.

      And of course Tinyhands Spraytan is barely distinguishable from Santos except Spraytan is more plainly a clinical case. In a just world, they’d both be hanging from a rope in the public square while the champagne corks are flying around.

      Speaking of which, how many more days until Eastman is disbarred? Not sure what the hold-up there is about.

      1. 12.2.1

        311-114 (after any due process considerations) does NOT support your desired narrative. There are have been far worse and far more egregious “vote the party line” results – MANY more such.

        This – of course- is of no surprise.

        You be you, Malcolm


            Please Pardon Potential re(P)eat (due to filter)

            Your comment is awaiting moderation.

            December 2, 2023 at 8:58 am

            Yes, Malcolm, your well known disregard for any type of Rule of Law for anyone outside of your own little bucket is well known.

            That cognitive dissonance of yours reigns supreme.

      2. 12.2.2

        No last minute bribes for that Last True Patriot, John Eastman, LBQ, Misfire?

        I’m disappointed.😂

    2. 12.3

      I paid Siroky for a consult. I told him Chastain was not on the board list. He told me Inwas crazy. So I went to another computer and saw she was listed on one that was not mine.
      All those attys. Knew that She and possibly the other two that were being protected from YMCA Night School. Tim Schaeffer died, Al Gore Sr. died while all if this was hidden and Schaeffer was wotking to protect Berkenstock and vice versa.
      So because Chastain was second in command to Bracy, Bracy left. Then Vick made sure.all my complaints were shredded. I got no letters back. But every year Schaeffer said Merry Christmas. After Vick left it was because Chastain finally became a real atty. So you tell the public what I know is a fact I can back up. Why would DOLL, Litman, and Lehman work the conspiracy to cover up the facts. And why did Gov. Lee only have Cartel Smith fired????
      Siroky was in a position to research what I showed him.
      Atty Terry Cox told me I was working with a short deck. But even he had no idea why James Todd sat back for Bryant III. Every lawyer, and citizen that was sanctioned, punished, and ignored has a case against the BOPR. Now Chastain is sitting in VICK’S seat????. Why would Chastain second in command, then first when Bracy runs away because he knows what the conspiracy is about, now sit as investigator? For one reason only. To make sure those she owes, and myself she blocks from complaints is why she sits there.
      Why are the board of Governors not made awzre?


            I never even knew this existed, until after a break-in. I found it in an envelope from Atty. James Schaeffer. I know that it is an attys. responsibility to do something whrn they research and find what was done. I’ll never understand why Lee did what he did. The buck did not stop at Cartel Smith.

  1. 10

    An entire patent does not rise and fall with the invalidation of 1 type of claim. A corollary is that a patentee only needs 1 claim to be valid and infringed. So, what does it hurt to include apparatus claims, method claims, MPF claims and Jepson claims in a single US patent application or in US continuations/divisionals?

    Should is the past tense form of shall. One could argue that shall means “should” vice “will.”

    1. 10.1

      PeteMoss – that is a very interesting Grammar lesson.

      I do wonder now if the 37 CFR section has the force of law to bind applicants (as opposed to binding the Office).

    2. 10.2

      …then again – as already noted – there is a HUGE caveat as to the discretion (and to whom that discretion is provided to), so even a “SHALL” is not the same as a MUST.

      See post 1 for the easy consideration that is that caveat.

    3. 10.3

      “An entire patent does not rise and fall with the invalidation of 1 type of claim.”

      My thought as well Pete.

      My only reason for not including them in my apps and patents is my concern with the off-the-rails CAFC or an infringer trying to have such Jepson claim(s) be treated as representative of one or more groups (or all groups / all) of my claims.

      That risk is too great.

      1. 10.3.1

        Yes, Pro Say – the risk IS the driver of the easy consideration (of the choice OF the applicant – per law).

      2. 10.3.2

        Any patent application filed outside the US, including a PCT application, needs to have multiple dependent claims, short sentences that contain only 1 limitation per sentence, a technical problem/solution discussion, at least one broad, unpatentable claim, and all statutory types of US claims. All claims can be filed as examples. Strong patent claims never see the Federal Circuit.


          Perhaps all sound suggestions – and ones that the client will have their say in.

          From experience though, clients simply are not that keen on having such divergent aspects, and as the US Market is (often) the predominant one, the US rules are often the stalking horse.

  2. 8

    Hey gang, anyone see the message from Kathi about the proposed raises?

    “Update on Special Rate Table (SRT) 0576 for certain patent professionals
    Dear Colleagues,
    Since my first days with the USPTO, I have heard your feedback on a number of pressing issues, including pay for patent professionals covered by Special Rate Table (SRT) 0576. You’re receiving this email because your position is among those classified under this SRT.
    For several months, I have been working alongside Patents, the Office of Human Resources (OHR), and union leadership teams on a strong proposal to implement an adjustment to SRT 0576.
    We recently submitted our business case requesting that adjustment.
    The Department of Commerce (DOC) has favorably reviewed and forwarded our request to the Office of Personnel Management (OPM) for their final review and decision. We will update you as soon as we hear from OPM, which could be in the next few weeks.
    The submitted package requests a multi-tiered increase to SRT 0576 as follows:

    Grade levels Increase percentage

    5, 7, 9 4%
    11, 12 6%
    13, 14, 15 9% ”

    I’m not sure if they mean for examiners as she doesn’t specify but I’m guessing that’s what she means. Anyone know what all the ins and outs are of this cap and all?

  3. 7

    If you’ve got an actual invention (e.g., something besides a computer with new instructions or content descriptors, or something other than a naturally occurring fact that you “detect” using old detection methods) then it doesn’t matter how you claim it.

    Of course, “hiding the ball” and larding up one’s claims with multiple paragraphs reciting the prior art (maybe using some trendy new lingo or some terms that the applicant just coined!) is a “strategy” of sorts if the goal is simply to get a patent past the PTO. But intelligent patent attorneys who are aware of the game aren’t fooled by that stuff, as has been demonstrated in this comment section countless times.

    1. 7.1

      Please please please tell me that you are not referring to yourself as one of those “intelligent patent attorneys.”

      You prove the opposite with most every post that you ‘contribute.’

  4. 6

    Just a quick note so nobody gets confused: as with the claims at issue in Mayo, there is no “magic trick” to rescue a claim of the scope that Ariosa was seeking. The only valid and eligible claim available would have recited at least one non-obvious (inventive) step that was also physically transformative.

    1. 6.1

      You do recall that “Machine or Transformation” is just a clue and not an actual legal requirement, right?

  5. 5

    While jepson claims are not mandatory, patentees are required to “particularly” point out the invention. If the invention is an improvement, and the improvement is buried as one element of a 20 element claim, there seems to be some basis for saying the patentee has not particularly pointed out the invention.

    1. 5.1

      There is exactly zero basis for what you are suggesting.

      The invention is the claim.
      As a whole.

      This is not difficult (unless for some reason you are trying NOT to understand).

      1. 5.1.1

        112(b) requires the claim particularly point out and distinctly claim the invention. This doesn’t make any sense from statutory interpretation if you say “the claim is the invention.”

        The claim must particularly point out the invention. That is the statutory language.


          Wrong – you are misreading 112(b). There is no issue between the claim as a whole and the claim — as a whole – particularly pointing out the invention.

          You seem to want to NOT take the claim as a whole – and you have zero legal basis for doing so.

      2. 5.1.2

        Further, “invention” and “claimed invention” are two separate definitions. See 100(a) and 100(j). From statutory interpretation, they can’t be the same thing, given they are expressly defined by the same statute distinctly.


          35 USC 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.

          35 USC 100(a): The term “invention” means invention or discovery.

          35 USC 100(j): The term “claimed invention” means the subject matter defined by a claim in a patent or an application for a patent.

          Go ahead and try again to make your point.

  6. 4

    As the chart above shows, this “should” requirement is obviously not being enforced or followed. “Should” is a middle ground between “shall” and “may” and indicates to me an obligation on the attorney’s part to actually consider whether “the nature of the case admits” such a claim form.
    The “should” is not a requirement and consequently it cannot be enforced. Should is not a middle ground between “shall” and “may.” Rather, “should” is just “may” with the addition of “pretty please can you do it this way.”

    There is no good reason — for an applicant — to file a Jepson claim. If the applicant gets nothing out of it, why use it?

  7. 3

    Experience in Europe reveals that even when you don’t file a Jepson at the Patent Office, the exercise of writing one can alert the drafter to the weaknesses in the argument for patentability and stimulate productive debate with the client about how best to impress the court that the contribution to the art isn’t obvious.

    As readers will know, the EPO’s default requirement for claim drafting is the so-called 2-part claim with the two parts separated by “characterized by” or “in that”. These 2-part claims are NOT to be equated with the Jepson format. Correctly formulated, they deliver the advantages Dennis sees, without the disadvantages.

    1. 3.1

      Let me (again) call this out as B$:

      These 2-part claims are NOT to be equated with the Jepson format.

      MaxDrei is attempting to preach about what will happen in the US Sovereign, even as he (perpetually) deigns not to understand the US Sovereign.

      1. 3.1.1

        No. Wrong. I’m writing to patent attorneys in the USA with clients who file at the EPO. My concern is to get them optimal protection in Europe.

        How do you come to the idea that a European 2-part claim is as disadvantageous to its owner in Europe as a Jepson is in the USA?

        Do you know how to draft a European 2-part claim, when it is appropriate, how it is construed after it issues, and when it is right to resist the EPO’s default requirement for such a claim? Are you one of those US patent attorneys who in the course of EPO prosecution refuse to countenance a 2-part claim at any price?

    2. 3.2

      I beg to differ.

      The two-part form of claims is not popular among all European patent attorneys. Personally, I prefer the US standard form.

      The recitation of elements in the first part is an admission that they are prior art. There is the risk of reading a piece of prior art with a broader scope than its real disclosure. For example, if the prior art discloses A1 and the invention includes A2, reciting in the first part of the claim a more general definition A which encompasses both A1 and A2 but is not part of the prior art leads to an admission of A as prior art which may be damaging.

      In addition, the division in two parts often leads to awkward drafting, because the second, supposedly new part may have to recite a feature which pertains to an element recited in the first part. Whereas the US one-part format allows all elements to be recited in a logical manner and minimises répétitions.

      Concerning the EPO practice, I am not aware of a rejection based on the applicant’s unwillingness to comply with the two-part format. When I have been requested to comply, I have argued that this would make the language of the claim awkward and the examiner would not insist.

      If the US is a major jurisdiction for a European applicant, it is certainly advisable to use the one-part format from the priority application. The problem in the US is also that the US « preamble » of a claim must not be equated to the first part of a European-style claim, since the features recited in the preamble are not considered limiting under US law, unlike the features recited in the first part of a European-style claim.

      1. 3.2.1

        Thanks, Francis Hagel, for that contribution. I agree with most of what you write. In particular, 2-part claim is often not good for the client.

        In such cases, I resist it even to the extent of disapproving an amended claim 1 text “intended for grant” which I get from the Examining Division with its Notice of Allowance. As you say, given strong enough reasoned dissent from the Applicant, the EPO tends to relent.

        But just as often, a 2-part claim serves very nicely, to emphasize patentability over the closest prior art starting point and (given the continuing relevance in Europe of the Doctrine of Equivalents) reinforce perceptions in the mind of competitors and would-be infringers that to ignore the patent might not be a good idea. Dennis does have a point, I would say.

        But, hey, I’m in engineering and you’re in chemistry. Your experience is is different from mine so your outlook will be too.

        I wonder how the pemetrexed litigation in Europe would have panned out, if a 2-part claim had been at the centre of it.

        As to your A, A1 and A2 claim interpretation point, will you tell me how the Applicant’s admission goes no further than to admit that the pre-characterizing features are disclosed in combination in D1? How do you come to the idea that it is an admission (like with a Jepson claim) that the pre-chracterizing part is “common knowledge” or “conventional”? Is this perhaps within your experience in a court under the EPC?



          Thank you for your reply.

          I don’t think our experiences are that different. I’m not in chemistry but in physics esp. geophysics and mechanics.

          As to A, A1 and A2 points, the examples I have in mind are not chemical such as the species/genus type, but simply A is a functional or broad definition of a feature, A1 and A2 are different embodiments of A. A1 is disclosed in the prior art, A is not. If you recite A in the first part of the claim, which is supposedly known, that may be used to advantage by an examiner or an opponent who may challenge inventive step by substituting the broad definition A for the more specific A1 in a combination with another prior art. The combination of A1 with this other prior art would be less effective since you could argue, based on A2 being different A1, that the combination fails to arrive at the claim.

          It is easy to fall prey to such generalisation when the two-part format is considered the standard.


            FH: I think I see what you are driving at. I don’t disagree. When D1 uses terminology different from that of the pending application, shoehorning the claim into 2-part form can carry Applicant into the notorious Bermuda Triangle, caught between the provisions of Art 54, Art 84 and Art 123(2) EPC. It is particularly galling, when an EPO Examiner issues a Notice of Allowance which includes a claim 1 divided by the Examiner into a 2-part form that deprives Applicant of the fair scope of protection to which it is entitled.


              Dear MaxDrei

              I am not aware of this “notorious Bermuda Triangle caught between the provisions of Art 54, Art 84 and Art 123(2) EPC.” You’ve piqued my curiosity. Would you mind explaining with an example ?

              As to a claim amendment entered by the Examining Division turning a one-part form into a two-part form, this is abuse and there are all reasons to resist. First, the principle is that the applicant is solely responsible for the claims as granted, hence applicant must be able to choose the drafting, subject to compliance with the EPC. Second, there is no legal basis for a two-part form in Article 84. Third, it opens up a new matter issue, because the change has the potential to alter the interpretation of a court in infringement proceedings (for example, arguments to support novelty/inventive step based on features located in the first part of the claim may be weakened just because these features are in the first part i.e. supposedly known. And the EPO incurs no liability if the patent is struck down by a court on this ground.


                Gladly, FH.

                The original “Bermuda Triangle” is an area of the Atlantic Ocean notorious for the mysterious disappearance of many sailing ships. The EPO-generated Bermuda Triangle is the area where many pending patent applications sil into, and then disappear.

                The vertices of the EPO’s BT are set by Art 54, Art 84 and Art 123(2) EPC.

                The ED asserts that the claim fails under Art 54. D1 robs the as filed claim of novelty. Applicant amends. But no matter how hard Applicant tries to establish patentable novelty, every proferred amendment is found to offend Art 84 or Art 123(2) EPC, or both. There is no escape. The application founders.

                This can happen even when it is manifestly clear to the skilled reader from the EPO opinion on patentability that patentable matter is present.

                The EPO’s shoulder-shrug reaction is that all one needs to stay out of the Bermuda Triangle is higher quality original patent drafting, that legal certainty for the public is of pre-eminent importance and that “fair” protection for the inventor is the responsibility of the drafter. It has a point, but that is of little consolation for those Applicants who cannot get to grant with their patentable contribution to the art.

                Fun, eh?

                Just curious about your scenario though. Is it so far only theoretical or have you already lived through a real case where the patent owner suffered as you describe?

                1. ^^^ Contrast with the US Supreme Court’s disdain of “scriviners” who DO “get around” the desired (anti-patent) edicts of the Judicial Branch by “higher quality original patent drafting“.

                2. Contrast, you say. What the EPO regards as competent drafting is writing, in the application as filed, a set of claims that converges in a series of steps from the inventive concept in its widest form to the best mode in its narrowest form, with each increment of scope-narrowing corresponding to a quantum step of substantively improved patentability, whereby no prosecution amendment is ever needed, other than to plug one of those dependent claims into claim 1. With such prosecution, there is no danger of falling into the Bermuda Triangle.

                  Believe me, there is at the EPO at least as much distain for scrivening as in the US Supreme Court.

                3. Please Pardon Potential re(P)eat (filter)

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                  Decmber 8, 2023 at 8:49 am

                  whereby no prosecution amendment is ever needed,

                  You certainly have not been paying attention to the US Sovereign.

                  That you spend SO MUCH time on this blog, and yet pay so little attention is a bl1ght.

                  That you never seem able to understand this only doubles down and renders your ‘contributions’ to be nigh w0rthless.

  8. 2

    FYI, and just a thought, but given that the decline to essentially zero is so pronounced, perhaps a log scale would provide a better graph.

  9. 1

    There is where getting out of the Ivory Tower pays dividends:

    Should is a middle ground between “shall” and “may” and indicates to me an obligation on the attorney’s part to actually consider whether “the nature of the case admits” such a claim form.

    This obligation is not only routinely performed, it is an extremely easy consideration to make, as MOST ALL nature of patent cases dictate against the use of the Jepson Claim Format.

    The mere (academic or bureaucratic) ‘want’ of “nice to read” or “easier to examine” is simply NOT considerations that (necessarily) play to the benefit of the innovator or protection of the innovation. Put bluntly, the decider of “as the case admits” is simply driven by the ‘ease to others,’ especially when that ease has been weap0n1zed against the innovator.

    I’ve been speaking to this very thing for well over a decade now.

    You yourself, whether or not fully aware, provide several baseline reasonings as to why “nature of the case” will only on the very rare and extreme case dictate (or admits to) that the (patent profanity laced) claim form be resorted to.

    I would take a moment here as well to recall several of my ongoing detractors and their own admitted desire not only for use of this form, but that it be greatly elevated to be some type of required form (yes, you, Greg-I-Use-My-Real-Name-Except-When-I-Use-Dozens-DeLassus).

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