In re Yasuhito Tanaka – An Improper Expansion of Reissue Law and Practice

February 28, 2014

By Stephen Marcus*

Patent LawIn re Yasuhito Tanaka[1] was issued by the U.S. Court of Appeals for the Federal Circuit (“CAFC”) on April 15, 2011, in an appeal of the precedential decision on reissue patents by the United States Patent and Trademark Office, Board of Patent Appeals and Interferences[2] (“BPAI” or “Board”) in Ex parte Yasuhito Tanaka[3].

In an expanded seven-member panel, the BPAI had held in Ex parte Tanaka that the reissue statute (35 U.S.C. § 251) “limits the scope . . . to grant reissue patents only in situations in which the original patent is deemed wholly or partly inoperative or invalid . . . by reason of the patentee claiming more or less than he had a right to claim in the patent,” and it disallowed the Tanaka reissue application on the basis that it simply added narrower claims, without changing the scope of independent patent claim 1, as a “hedge against possible claim invalidity.”[4] However, on April 15, 2011, in a divided three-judge panel, the CAFC reversed and remanded the BPAI decision, citing “the Board’s determination is contrary to longstanding precedent of this court.”[5]

The CAFC decision concluded that it was legally permissible to file for, and obtain, a reissue patent in which the “error” corrected by the reissue was to add one or more dependent claims as a “hedge against possible invalidity of original claims.”[6] The majority’s basis for approving the reissue patent was essentially a 50-year-old decision, In re Handel[7], which had nothing to do with the issue described below, but did contain dicta to the effect that it was permissible to add claims via reissue, not merely to correct an error in scope of the original patent claims, but also to add claims as “a hedge against possible invalidity.”[8] Obviously, the “hedge against possible invalidity” language does not correct any error of the original patent’s being too broad, or too narrow, or for that matter, being indefinite.

The Tanaka case was decided based on the pre-AIA version of the reissue statute, 35 U.S.C. § 251, which provides in its first paragraph that:

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 the 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. No new matter shall be introduced into the application for reissue.[9]

Post-AIA 35 U.S.C. § 251(a) contains language that is essentially identical to the first paragraph of pre-AIA 35 U.S.C. § 251.

The Tanaka prosecution history shows that a reissue application was initially filed to broaden the claim coverage based on an error recited in the accompanying reissue declaration, which stated that the originally patented claims were too narrow.[10] The examiner rejected the broadened claims and confirmed the originally patented claims as still being patentable.[11] The applicant later submitted a substitute reissue declaration, which asserted a new dependent claim that depended from initial patent independent claim 1.[12] When the examiner rejected the claims in the substitute reissue declaration, Tanaka appealed to the BPAI, where an expanded panel of seven judges affirmed the examiner’s rejection in a precedential opinion.[13] Tanaka then filed an appeal with the CAFC, which reversed and remanded the BPAI decision.

Obviously, if claim 1 of the original patent was truly patentable, (and the examiner in the reissue application agreed that it was), then merely adding a new dependent claim that depended from claim 1 did not cure any error of claiming “more or less than the patentee had a right to claim in the original patent” for these reasons:

  1. Certainly, the dependent claim did not broaden the patent coverage, since any device that infringed the new dependent claim would necessarily have infringed the existing patent claim 1.
  1. Further, the narrowing aspect of the new dependent claim did not cure any error existing in the original patent, since patented claim 1 was confirmed as being patentable by the examiner in the reissue application.

In Tanaka, adding a new dependent claim did not comply with the language of the reissue statute, and subsequent reissue applications filed “to provide a hedge against possible claim invalidity,” will also not comply with either version of Section 251.

There is no language in 35 U.S.C. § 251, (either pre-AIA or post-AIA) that can be interpreted as permitting reissue of a patent by adding one or more dependent claims (or independent claims for the invention claimed in the patent) to cure the “potential” or “inchoate” error that one or more original comprising-type patent claims might later be adjudicated to be invalid. Therefore, it is the author’s opinion that Tanaka was wrongly decided by the CAFC, and that the USPTO should seek to correct the law on this issue.

Click here to read Stephen Marcus’s full article on Tanaka, which was published in Volume 95, Issue 4 of the Journal of the Patent and Trademark Office Society on January 3, 2014. The journal is available for purchase at

* Stephen Marcus’s bio is located on this website here.
[1] In re Tanaka, 640 F.3d 1246, (Fed. Cir. 2011). This decision is hereinafter referred to as “Tanaka,” except where attached to a citation of the reported decision.
[2] Pursuant to 35 U.S.C. § 6 of the Leahy-Smith America Invents Act (the “AIA”), as of September 16, 2012, the Board of Patient Appeals and Interferences (the “BPAI”) has been renamed the Patient Trial and Appeal Board (the “PTAB”).
[3] Ex parte Tanaka, BPAI Appeal No. 2009-000234 (BPAI Dec. 9, 2009), 2009 WL 5819322 (2009). This decision is hereinafter referred to as “Ex parte Tanaka.”
[4] Id. at *12.
[5] In re Tanaka, supra at 1247.
[6] Id. at 1249-51.
[7] Id. at 1249-50.
[8] Id. at 1249. (Emphasis, in bold, added).
[9] Pre-AIA 35 U.S.C. § 251, first paragraph. (Emphasis, in bold, added).
[10] In re Tanaka, supra at 1247-48.
[11] Id. at 1248.
[12] Id. at 1247.
[13] 1248.

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