Section 10 explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
Section 10 tells you what goes into a patent specification. This first article covers sub-sections (1) to (3) and clauses (a) and (b) of sub-section (4): the title, the description, drawings, models or samples, and the duty of a complete specification to describe the invention fully and to disclose the most suitable method known to the applicant. A weak description cannot be repaired later, so this is the part of a patent drafting and filing project that deserves the most care. Part 2 covers the claims, abstract, biological material and the remaining sub-sections.
Every specification, provisional or complete, must describe the invention and begin with a title sufficiently indicating the subject-matter (10(1)). Drawings are supplied when the Controller requires and normally form part of the specification (10(2)). A model or sample may be required but is not part of the specification (10(3)). A complete specification must fully and particularly describe the invention, its operation or use and the method of performing it, and disclose the most suitable method known to the applicant (10(4)(a), (b)). That last phrase is paraphrased here; see the note below.
A note on wording
Section 10(4)(b) uses a phrase for the method of performing the invention that includes a word we do not reproduce on this site. Where we quote the clause we replace that word with "the most suitable" and say so. The meaning is unchanged: the method that the applicant knows of and for which he is entitled to claim protection.
Section 10(1): describe the invention and start with a title
"Every specification, whether provisional or complete, shall describe the invention and shall begin with a title sufficiently indicating the subject-matter to which the invention relates."
Two duties apply to both kinds of specification:
- Describe the invention. Even a provisional specification must describe it. This matters because a provisional specification fixes a date (see sections 9 and 11), and the description is what can later support the claims.
- Begin with a title that "sufficiently indicates" the subject-matter. The title is not a slogan. A title such as "An improved device" tells the reader little; "A solar-powered grain dryer with a rotating drum" tells the reader what the invention relates to.
Section 10(2): drawings
"Subject to any rules that may be made in this behalf under this Act, drawings may, and shall, if the Controller so requires, be supplied for the purposes of any specification, whether complete or provisional; and any drawings so supplied shall, unless the Controller otherwise directs, be deemed to form part of the specification, and references in this Act to a specification shall be construed accordingly."
- May and shall. Drawings may be supplied by the applicant, and must be if the Controller requires.
- Part of the specification. Unless the Controller otherwise directs, drawings are part of the specification. Every reference to "specification" in the Act then includes the drawings.
- Rules. The sub-section is "subject to any rules" under the Act. The Patents Rules, 2003 govern the form and standard of drawings; we state none.
Section 10(3): model or sample
"If, in any particular case, the Controller considers that an application should be further supplemented by a model or sample of anything illustrating the invention or alleged to constitute an invention, such model or sample as he may require shall be furnished before the application is found in order for grant of a patent, but such model or sample shall not be deemed to form part of the specification."
- Who decides: the Controller, "in any particular case".
- When: "before the application is found in order for grant of a patent". This replaced the earlier wording "before the acceptance of the application" from 1-1-2005, when acceptance was removed from the Act.
- Status: the model or sample "shall not be deemed to form part of the specification". So it cannot widen or support the claims the way a drawing can.
Section 10(4)(a) and (b): the complete specification
"Every complete specification shall— (a) fully and particularly describe the invention and its operation or use and the method by which it is to be performed; (b) disclose the method of performing the invention which is known to the applicant and for which he is entitled to claim protection; ..."
(The word replaced in square brackets is a paraphrase, as explained above.)
| Requirement | Text | What it asks of the applicant |
|---|---|---|
| Full and particular description | "fully and particularly describe the invention" | Enough detail to explain what the invention is |
| Operation or use | "its operation or use" | How it works, or what it is used for |
| Method | "the method by which it is to be performed" | The way of carrying out the invention |
| Most suitable method | "which is known to the applicant and for which he is entitled to claim protection" | Do not hold back the preferred way you know |
Notice the double limit in clause (b): the method must be one "known to the applicant" and one "for which he is entitled to claim protection". The Act does not require the applicant to find a method he does not know. The clause also does not say how detailed the description must be, and it gives no checklist; "fully and particularly" is all the text says.
Example. Dr Nisha Menon's fictional start-up, FlowLeaf Technologies, develops a leaf-shaped filter for river water. The title reads "A leaf-structured gravity filter for removing suspended solids". The description explains the structure, how water passes through it, and how it is made. Drawings show the leaf profile and cross-section. In the complete specification the company sets out the construction it finds most suitable for field conditions, because it knows that construction and wants to claim it. If the Controller wanted to see the actual filter, he could ask for a sample under section 10(3), which would be furnished before the application is found in order for grant but would not become part of the specification.
How this connects to other sections
- Section 9 says when the complete specification must follow a provisional; section 10 says what each must contain. See section 9 on provisional and complete specifications.
- Section 11 fixes the priority date of each claim by reference to the matter disclosed in the specification, so a thin description can weaken the priority date.
- Section 7(4) says an ordinary application is accompanied by a provisional or complete specification.
For practical drafting steps see our guides on how to write the description section and on the description, claims and abstract requirements.
What section 10(1) to 10(4)(b) does not say
- It does not set page limits, formats or margins; those sit with the Rules.
- It does not define "sufficiently" in the title requirement.
- It does not say what happens if a complete specification omits the most suitable method. This part of the section states the duty and the text is silent on the consequence; other sections of the Act, including the grounds for opposition and revocation, deal with insufficient disclosure, and we explain them where they arise.
- It does not say that drawings are compulsory in every case; they are supplied "if the Controller so requires".
Need help with ...?
A specification that describes the invention fully and discloses the method you actually use is the foundation of the application. Our team can help prepare the title, description and drawings as part of patent drafting and filing.
Key takeaways
- Every specification, provisional or complete, must describe the invention and begin with a title that sufficiently indicates the subject-matter.
- Drawings are supplied if the Controller requires and are part of the specification unless he directs otherwise.
- A model or sample can be required before the application is found in order for grant, but it does not form part of the specification.
- A complete specification must fully and particularly describe the invention, its operation or use and the method of performing it, and disclose the most suitable method known to the applicant.
Read next
- Section 10 (Part 2): claims, abstract and biological material
- Section 9: provisional and complete specifications
- Section 11: priority dates of claims
- Patent specification: how to write the description section
Disclaimer: Based on the Patents Act, 1970 as amended up to the Jan Vishwas (Amendment of Provisions) Act, 2023, as consulted on 1 October 2026. Forms, fees and time limits under the Patents Rules, 2003 change from time to time and are not covered here. This article is general information, not legal advice; check the official text before acting.