October Term 2001 · Docket 00-1543

Does a patent holder lose rights by changing claim language?

Festo seeks to limit the doctrine of equivalents. Shoketsu argues the doctrine remains broad.

Official caption
Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.
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Official Transcript

Verified source milestones

  1. — An official oral-argument transcript was verified.

The arguments, in order

This case may have been argued more than once. Each entry below uses that session's official transcript. Later arguments do not erase earlier ones.

  1. Argument 1 ·

    What happened at the argument

    Mr. Neustadt addressed a question from Justice Breyer.

    Mr. Bork referred to the parties as SMC.

    Chief Justice Rehnquist confirmed the case number.

    Mr. Wallace responded to a question from the Chief Justice.

    Read the official transcript for this argument · Official argument details

    Sources used for this argument breakdown

A citizen's guide to the whole case

What this case is about

The dispute centers on the scope of patent protection. Festo argues that changing claim language limits the patent. Shoketsu contends the doctrine of equivalents still applies broadly.

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How the case got here

The Supreme Court heard oral argument in this case on January 8, 2002.

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What each side wants

Festo wants the Court to limit the doctrine of equivalents.

Shoketsu wants the Court to maintain broad patent protection.

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What each side says

Festo argues that amending claims restricts the patent scope.

Shoketsu argues that the doctrine of equivalents remains fully applicable.

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What the justices asked

Chief Justice Rehnquist asked about a specific statutory section.

Justice Breyer asked about the scope of the doctrine.

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Why it matters

The outcome defines the boundaries of patent rights. It affects how inventors draft claims. It impacts the cost of patent litigation. It shapes the balance between innovation and competition.

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What happens next

This article currently covers the argument record. Use the official docket link for later case activity.

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Official Court provenance

Official docket and case history · Official Supreme Court oral-argument detail page

Title and summary sources

Revision history

  1. Revision 1 · Official Transcript ·

    Correction: Rewritten to the concise citizen-facing editorial standard.

  2. Revision 2 · Official Transcript ·

    Correction: Migrated to the dated official Court activity contract without model use.

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