Why “Characterized in That” Often Needs Reworking for U.S. Patent Claims

A Chinese independent claim often separates the known part of the solution from the distinguishing features with “其特征是” or “其特征在于.” Translating that phrase as “characterized in that” can be perfectly faithful. The problem is that U.S. claim practice assigns legal significance to certain two-part improvement formats. The phrase is not forbidden, but a China-originated claim should be re-evaluated before its structure is carried into the U.S. record unchanged.

Why Two-Part Claims Are Normal in China

China's Implementing Regulations provide a formal two-part structure for an independent invention or utility-model claim. The preamble identifies the subject matter and the necessary technical features shared with the closest prior art. The characterizing portion, introduced by language such as “其特征是……,” states the technical features that distinguish the invention from that closest prior art. The Regulations also recognize that some inventions are not suitable for that format and may be claimed another way.

For a Chinese drafter, this structure is therefore not an admission made casually in prose. It is part of the domestic claim-drafting framework. The PCT system has a similar concept: Rule 6.3 says that, whenever appropriate, a claim may contain a prior-art portion followed by a characterizing portion introduced by “characterized in that,” “characterized by,” “wherein the improvement comprises,” or words to the same effect.

That history explains why a literal English translation can look natural to a Chinese or PCT practitioner. It does not answer how the same structure will function in the United States.

The U.S. Analogue Is the Jepson Claim

U.S. regulation 37 C.F.R. §1.75(e) describes an improvement claim format commonly called a Jepson claim. Where appropriate, the claim contains a preamble describing the conventional or known elements or steps of the combination, a phrase such as “wherein the improvement comprises,” and then the elements, steps, or relationships the applicant considers to be the new or improved portion.

This superficial similarity matters because U.S. law attaches consequences to Jepson form. Current MPEP §2129 states 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. The implication can be overcome in appropriate circumstances, and the rule is not an irrebuttable admission in every case. But it is a consequence that a Chinese applicant should not create inadvertently merely because the source claim happened to use a two-part structure.

The problem is not the English phrase by itself

“Characterized in that” is not a banned U.S. expression. The risk comes from the overall claim structure and record—particularly whether the claim is understood as identifying the preamble as conventional or known and the following language as the improvement.

Why the Implied-Admission Issue Matters

Patent prosecution is cumulative. Statements and drafting choices that help organize the application today can become evidence used to interpret the record later. If the applicant has no strategic reason to concede that a broad set of preamble features represents the prior art of another, a Jepson-like structure can give away a proposition that did not need to be conceded.

The consequence can appear in novelty and obviousness analysis. It can also affect claim construction because a true Jepson preamble is not merely contextual; it forms part of the claimed combination and helps define the claim's scope. The applicant therefore needs to know whether it is deliberately using an improvement claim or simply preserving the Chinese layout out of habit.

This is especially important when the Chinese preamble was drafted with “closest prior art” in mind for domestic formal reasons. The U.S. case may involve a different prior-art record. Treating every Chinese preamble feature as a U.S. admission can be strategically unnecessary.

Why the Correct Advice Is Not “Never Use It”

There are situations where a Jepson claim can be purposeful. The U.S. regulation still describes the form, and it can state the improvement with unusual clarity. The correct advice is therefore not to run a global search-and-replace that converts every “characterized in that” into another transition word.

Nor is “wherein” a magic cure. If the overall claim still expressly presents the preceding elements as conventional and the following elements as the improvement, changing the transition alone may not change the substance. Conversely, a claim can be drafted in ordinary U.S. combination form without any implication that all preamble material has been admitted as prior art.

What U.S. Adaptation Should Actually Rebuild

A proper adaptation starts by identifying what the independent claim needs to cover commercially, which limitations are genuinely necessary, and what the original disclosure supports. The drafter can then decide how to organize the claim without importing a concession from the Chinese format.

That may mean moving some Chinese preamble features into the body, removing unnecessary statements about what is known, or drafting the entire combination as a single set of positive limitations. It may also mean preserving a purposeful preamble because the preamble supplies an important structural context. The answer is claim-specific.

For dependent claims, the issue is usually simpler: a literal “according to claim X, characterized in that…” construction often reads awkwardly in U.S. English. The U.S. dependent claim can normally recite the additional limitation directly after properly incorporating the parent claim, without retaining the Chinese characterizing phrase.

A China-to-U.S. Claim Review Checklist

Identify whether the Chinese claim is deliberately distinguishing the closest prior art or merely following domestic form.
Do not assume the Chinese preamble should be treated as admitted prior art in the United States.
Determine whether the intended U.S. claim is actually meant to be a Jepson improvement claim.
If not, rebuild the independent claim as a U.S. combination claim using positive limitations supported by the original disclosure.
Do not rely on replacing “characterized in that” with “wherein” without reviewing the structure and meaning of the whole claim.
Confirm that dependent claims use clear U.S. dependency language and preserve antecedent basis.
Keep a record of what was changed for U.S. adaptation so fidelity to the priority disclosure can be checked.

Takeaway

“Characterized in that” is a good example of why patent translation is not ordinary translation. The phrase can be correct English, can be consistent with Chinese rules, and can be recognized under the PCT—yet still be the wrong default for a U.S. claim because the U.S. system gives improvement-claim structure its own consequences.

The goal is not to erase every visible trace of Chinese drafting. It is to prevent a domestic drafting convention from making an unintended U.S. admission. When a Chinese application enters the United States, the claim should be rebuilt around the U.S. scope and record the applicant actually intends.