In re Tanaka, No. 2010-1262, 640 F.3d 1246, 98 USPQ2d 1331 (Fed. Cir. April 15, 2011) Reissue is an appropriate means to add a narrower dependent claim, according to the April 15, 2011, Federal Circuit decision In re Tanaka, even if the original claims are retained unchanged. The Federal Circuit held that a patentee is permitted to “hedge” against possible invalidity using the reissue statute 35 USC §251, because omission of a narrower claim in an original patent can render the patent “partly inoperative” by failing to disclose the invention to the full extent permitted by law, and therefore qualifies as an “error” correctable by the reissue procedure. Reissue is permitted where an error has occurred during prosecution:

Whenever any patent is, through error without any deceptive intention, deemed wholly or partly inoperative or invalid, by reason of a defective specification or drawing, or by reason of the patentee claiming more or less than he had a right to claim in the patent, the Director shall, on surrender of such patent and the payment of the fee required by law, reissue the patent for the invention disclosed in the original patent, and in accordance with a new and amended application, for the unexpired part of the term of the original patent.

35 U.S.C. § 251. Unlike the re-examination process, a patent submitted for reissue is not examined, but claims may be narrowed or, if a request for reissue is filed within 2 years of patent grant, they may broadened. A patentee must surrender the patent to the patent office for reissue, and a new “reissue patent” is issued to supplant the original patent. The Federal Circuit has interpreted the statute to include two requirements in order to invoke a reissue proceeding: (1) a patent must be “wholly or partly inoperative or invalid” and (2) “the defective, inoperative, or invalid patent” must have arisen “through error without deceptive intent. Hewlett- Packard Co. v. Bausch & Lomb, Inc., 882 F.2d 1556, 1564-1565 (Fed. Cir. 1989). The term “inoperative” has been interpreted to mean “ineffective to protect the invention.” See Hewlett-Packard, 882 F.2d at 1565.


Tanaka filed a reissue application two years after the issue date, initially to broaden the claims, stating in a declaration that the original claims “did not adequately define the invention because they were more specific than necessary.” During the course of reissue, however, Tanaka ended his pursuit of broader claims and instead filed a new narrower dependent claim. The Examiner rejected the narrower claim stating that because the “original claim 1 remains in the current reissue application, [and] the broadest scope of the patent remains the same,” the new narrower claim did not present the type of error correctable by reissue under 35 U.S.C. §251. See 98 USPQ2d at 1332. The Board affirmed in a precedential opinion of a panel of seven judges. The Board reviewed a number of CCPA and Federal Circuit cases, determining that the statute was “a remedial provision, which should be construed liberally,” for example, claims may be corrected by reissue, but that the appellate court had only addressed the issue before it in dicta. Ex parte Yasuhito Tanaka, No. 2009-000234, 93 USPQ2d 1291, 1296 (BPAI Dec. 9, 2009) Finding no controlling authority on the subject, the Board held that 35 U.S.C. §251 did not allow simply adding narrow claims to the reissue patent when there is no assertion of inoperative or invalidity of the existing claims. 93 USPQ2d at 1296. The Board found that Tanaka was impermissibly seeking an additional claim “in order to hedge against the possible invalidity of one or more of the original claims”. [I]n the present case, the original patent claims are not being amended to correct a defect that could render the claims invalid. Rather, the original patent claims are not being corrected at all. The Appellant is simply seeking, by reissue, to add narrower claims, where no valid assertion has been made by the patentee that any error exists as to the scope of the original patent claims.

93 USPQ2d at 1296. Citing Patent Office policy that has been applied since July 2008, the Board pointed out that [s]ection 1402 of the MPEP states that the Patent Office’s interpretation of §251 does not allow for a reissue application in which the only error specified to support reissue is the failure to include one or more claims that is/are narrower than at least one of the existing patent claims(s) without an allegation that one or more of the broader patent claims(s) is/are too broad together with an amendment to such claim(s).

93 USPQ2d at 1296. Tanaka appealed. The issue presented on appeal was: “Has the Appellant shown that the Examiner erred in determining that the presentation of a narrower claim in a reissue application that still contains all of the original patent claims does not present the type of error correctable by reissue under 35 U.S.C. § 251?” App. Br. at 5.. The Federal Circuit reversed and remanded, finding the Board’s decision “contrary to longstanding precedent of this court.” 98 USPQ2d at 1331, 1332.


The PTO had argued that omission of a dependent claim does not render a patent “partially inoperative” under §251, because the subject matter of a dependent claim is necessarily covered by the claim from which it depends. The PTO also argued that the failure to include such a new dependent claim during original prosecution did not constitute “claiming more or less than the patentee had a right to claim in the patent,” i.e., it was neither an “over-claiming” nor an “underclaiming” error. Tanaka argued that the Board’s conclusion was contrary to binding precedent of the Federal Circuit, because §251 allows the addition of narrower claims to existing claims as a hedge against the possibility that the existing broader claims may be found invalid. Id. The Federal Circuit agreed with Tanaka, stating that “adding dependent claims as a hedge against possible invalidity of original claims” was permitted by precedent, and that the Board’s determination “flies counter to principles of stare decisis”. 98 USPQ2d at 1332. The Court stated that in a case before its predecessor court, the Court of Customs and Patent Appeals, that presented nearly identical facts, Judge Giles S Rich “clearly stated that adding dependent claims as a hedge against possible invalidity of original claims ‘is a proper reason for asking that a reissue be granted.’ ” Id. at 1333, quoting In re Handel, 312 F.2d 943, 946 n.2 (CCPA 1963). Under Handel, a patent may be wholly or partly inoperative under §251, if the claims do not “adequately protect the invention, which may be due to failure of the solicitor to understand the invention.” Id., citing Handel, 312 F.2d at 945, n. 2. The majority determined that in Handel, Judge Rich felt that “less” was used in the sense of fewer claims than could have been made, rather than the scope of subject matter included within the existing claims. Id. For example, narrower subject matter may be claimed by adding limitations to an existing claim or adding dependent claims that recite the limitations. Hence, according to Judge Rich, the use of reissue to hedge possible invalidity of broader claims by adding claims of narrower scope was “a proper reason for asking that a reissue be granted”. Id., quoting Handel, 312 F.2d at 945, n. 2.

The majority recognized that these statements have been characterized as dictum, and the “Handel” rule had “seemingly never been formally embodied in a holding of this court or its predecessor.” 98 USPQ2d at 1333-1334. However, the Court found Handel was “not simply a passing observation – it was a considered explanation of the scope of the reissue authority of the PTO in the context of a detailed explanation of the reissue statute” and noted that neither the Federal Circuit nor its predecessor court have departed from it. Id. The Court determined that later cases cited Handel favorably or followed its dicta. Id. (citing In re Muller, 417 F.2d 1387 (CCPA 1969); and Hewlett- Packard, 882 F.2d 1556). Thus, in view of the adoption of the rule in Handel “that adding a dependent claim as a hedge against possible invalidity is a proper reason to seek reissue” and the Court’s adherence to the rule in both Muller and Hewlett-Packard, the Federal Circuit rejected the Board’s “contrary” ruling. 98 USPQ2d at 1334.

The Court rejected the PTO’s assertion that it is not error under § 251 to omit a narrower dependent claim from an original patent because such an omission does not render the patent inoperative, finding that “the omission of a narrower claim from a patent can render a patent partly inoperative by failing to protect the disclosed invention to the full extent allowed by law.” 98 USPQ2d at 1334. The Court reasoned that narrower dependent claims are less vulnerable to validity attacks than broader independent claims and noted that “each claim of a patent has a purpose that is separate and distinct from the remaining claims.” Id. For example, dependent claims can be “useful to clarify the meaning of broader, independent claims under the doctrine of claim differentiation.” Id. at 1334 (citation omitted). The Court distinguished application of the Handel rule from the situation in which a patentee impermissibly files a reissue application in order to have the claims re-examined in view of newly discovered prior art without alleging any defect or error in the patent. The Board had raised this comparison in support of its decision. The Court stated:

Applying for a reissue that adds only narrower claims without amending any of the original claims is not the same as a “no defect” reissue.

Tanaka, 98 USPQ2d at 1334. Rather, error in the original prosecution in accordance with §251 may be found where the applicant neglects to seek a narrower dependent claim to which he was entitled. Id.


In dissent, Judge Dyk disagreed that precedent required the majority’s result, stating that, in fact, “the prior cases have ‘never squarely addressed the issue, and have at most assumed the applicability of [a particular] standard,’ [therefore] we are not bound by those decisions and remain ‘free to address the issue on the merits’ in subsequent cases.” 98 USPQ2d at 1335, J. Dyk dissenting (citations omitted). Distinguishing the cases cited in support of the majority opinion, the dissent’s position was that the Hewlett-Packard court made clear it wasn’t deciding whether hedging was permitted, but rather assumed that practice was in accordance with the reissue statute’s remedial purpose, and that the footnote in Handel stating that additional narrower claims were proper in reissue as a “hedge against possible invalidity” was dicta. Id. Tanaka had raised Handel in support of its position on appeal to Board of Appeals and Patent Interferences, but the Board also had concluded that the footnote in Handel was dicta: [T]he CCPA’s tacit approval in a footnote that it is proper to seek narrower claims in a reissue as a hedge against the possible invalidity of the original claims is a voluntary opinion made by the court which falls outside the holding of the court in Handel and which was made without argument or full consideration of the point after briefing by the parties. In other words, this statement in footnote 2 of Handel is dictum.

93 USPQ2d at 1295. The dissent stated that §251 is intended to provide patentees “with an opportunity to correct errors” but in this case “applicants made no correction to the original patent; instead, they merely attempted to add claims to the original patent.” 98 USPQ2d at 1336, J. Dyk dissenting. Judge Dyk observed that the clear language and purpose of the statute supported the PTO’s position because: The required premise of the statute that the original claims were ‘deemed’ wholly or partly inoperative or invalid’ as the result of an ‘error’ is entirely missing. There is no assertion that correction of anything in the original patent was required. Id.