Episode 31

This article explains exclusion claim in claims amendments and corrections.
An "exclusion claim" is a claim that explicitly excludes only some of the matters encompassed by the claimed invention from the claims, while leaving the stated matter intact (Examination Guidelines, Chapter 2, 3.3.1(4) - Amendments to Include Exclusion claim).
This article explains "exclusion claim" by citing the Intellectual Property High Court Grand Bench Decision of May 30, 2008, Case 10563 (Gyo-Ke) of 2006.
As a prerequisite for determining whether a correction to include a "exclusion claim" is permitted, this decision presented the following general criteria for determining whether a correction "within the scope of the matters described in the specification or drawings" is required under the Patent Act.
"'Matters described in the specification or drawings' are those matters disclosed to third parties as a prerequisite for obtaining a monopoly through patent rights for inventions that are creations of highly advanced technical ideas. Therefore, the 'matters' referred to here are presumably technical matters related to the invention disclosed in the specification or drawings. 'Matters described in the specification or drawings' are technical matters that can be derived by a person skilled in the art by combining all of the descriptions in the specification or drawings. If an amendment does not introduce new technical matters in relation to the technical matters derived in this way, the amendment can be said to be made 'within the scope of the matters described in the specification or drawings.'"
The court then held as follows, clarifying that the general standard of judgment applies even when requesting a correction to exclude, by means of a so-called 'exclusion claim' a portion of an invention in a patent application that is identical to an earlier invention that was not publicly disclosed at the time of filing the patent application.
"...because the patentee is unaware of the existence of the prior invention at the time of filing the patent application, the specification or drawings of the patent application usually do not contain any specific description of the prior invention. However, the proviso to Article 134-2, Paragraph 1 of the Patent Act still applies to corrections that correct matters not specifically described in the specification or drawings. As long as such corrections are deemed not to introduce new technical matter into the technical matters disclosed by the descriptions in the specification or drawings, they should be considered corrections made 'within the scope of the matters described in the specification or drawings.'
It is not appropriate to assume that amendments to make a 'exclusion claim' are inherently unacceptable. In other words, even when the amendments are made in a negative manner, such as in an amendment to make a 'exclusion claim,' if the matters to be amended are matters described in the specification, etc., then, just as in the case of amendments that involve positive descriptions, it can be said that no new technical matter is introduced unless there are special circumstances. However, conversely, just because the matters to be amended themselves are not described in the specification, etc., does not mean that the amendment introduces new technical matter.
Therefore, whether an amendment to create a "exclusion claim" can be said to be made "within the scope of the matters described" in the specification, etc., should ultimately be judged based on whether the amendment does not introduce new technical matters in relation to the technical matters described in the specification, etc.