Canada: Pulling Out All The Stops - Patenting Computer Implemented Inventions In Canada Despite Unprecedented Obstacles

Last Updated: January 18 2016
Article by Isi E. Caulder and Nicholas Aitken

Patent practitioners are facing unprecedented obstacles to patenting computer implemented inventions in Canada. The primary challenge rests in overcoming widespread rejections based on unpatentable subject matter raised by Canadian patent Examiners. Patent examination at the Canadian Intellectual Property Office (CIPO) is governed by the self-published Manual of Patent Office Practice (MOPOP)1 and supplementary Practice Notices.2 Generally speaking, CIPO issues Practice Notices and revisions to the MOPOP to bring their examination practice into compliance with the latest jurisprudence and legislation.

Two such Practice Notices3 directed to purposive construction and computer-implemented inventions were issued in 2013 in response to the decision of the Canadian Federal Court of Appeal in Amazon.4 These Practice Notices (the "2013 Practice Notices") have been the subject of much criticism by the Canadian patent bar for their apparent inconsistency with the decisions of the Supreme Court in Free World Trust5 and Whirlpool,6 especially with regard to the identification of essential claim elements by purposive construction.

This article explores and details several response strategies which have been successful at overcoming patentable subject matter rejections made under the 2013 Practice Notices. Although it is helpful to understand the inconsistency between the 2013 Practice Notices and the current state of the law, arguments on this basis appear to be largely ineffective. Instead, an in-depth survey of recently allowed Canadian patent applications reveals that arguments that are strategically aligned with the framework of the 2013 Practice Notices are most effective in achieving allowance.

Identification of Essential Claim Elements

Purposive construction dictates that the language of a claim must be read in an informed and purposive way. More specifically, claim language must be given the meaning as would be understood by a person skilled in the art, as of the publication date, having regard to the specification. In one aspect, purposive construction identifies claim elements as essential or inessential. Statutory requirements of subject matter, novelty, and inventiveness are assessed based on the essential claim elements without regard to the inessential claim elements.

The Canadian Supreme Court in Free World Trust and Whirlpool established a presumption that all claim elements are essential, and stated that a claim element is inessential if:

(i) it was obvious to a skilled person at the time of publication that a variant of the claim element would not make a material difference to the way the invention works, and

(ii) the language of the claim, expressly or by inference, did not suggest that the patentee intended the claim element to be essential, irrespective of practical effect.

In contrast, the 2013 Practice Notices establish a very different test for essentiality, which can be summarized as follows:

(i) identify the "problem" to which the application is directed by reference to the description and common general knowledge, and

(ii) identify the elements necessary for the successful resolution of that problem as being essential.7

This test has been criticised as lacking any clear basis at law. More importantly, the 2013 Practice Notices appear to lead Canadian Examiners to apply the CIPO's version of the essentiality test in a manner that is decidedly hostile to software inventions.

Assessment of Whether Claimed Subject Matter is Statutory

To be valid and enforceable, a patent claim must be directed to an invention within the meaning of the Patent Act.8 Section 2 of the Canadian Patent Act defines an invention "as any new and useful art, process, machine, manufacture or composition of matter, or any new and useful improvement in any art, process, machine, manufacture or composition of matter."9 The court in Amazon further pronounced that "patentable subject matter must be something with physical existence, or something that manifests a discernible effect or change."10

In the context of patent applications for software inventions, computer components, such as processors, are often recited in the claims to ground the software in tangible hardware which satisfies the physicality requirement set out in Amazon. However, the 2013 Practice Notices attack such computer hardware as being unnecessary to satisfying the identified problem and thus inessential and ignored in assessing whether the claimed subject matter is statutory. For example, the 2013 Practice Notices state that if the claimed software steps can be performed by pen and paper, no matter the inconvenience or impracticality, then the recited computer hardware is inessential.11 A claim without a tangible essential element is typically rejected as being abstract, a mental process, or a scheme which does not fall into a statutory category of invention.

The analysis established by the 2013 Practice Notices determines whether an element is essential based on whether the same result can be obtained without that element. This is very different from the test pronounced in Free World Trust, which asks whether an element is essential based on whether omitting or substituting an element would affect the way the invention works.

For most software inventions, performing the software steps with pen and paper would dramatically affect the way the invention works. Indeed, many software inventions would lose all practical utility if performed by hand. Moreover, the analysis of the 2013 Practice Notices completely ignores whether the patentee intended a claim element to be essential irrespective of practical effect.

Lessons Learned from Recent Patent Prosecution

Anecdotally, Canadian patent Examiners have taken up a practice of rejecting software inventions by first determining that all of the tangible computer hardware is inessential as being unnecessary to solve the problem (e.g. capable of substitution by pen and paper), and then finding the remaining essential elements to be abstract, a mental process, or a scheme which does not fall into a statutory category of invention.

Although such rejections have proven difficult to overcome, a survey of recently allowed applications has shown some success in applying the following response strategies:

#1: Emphasize that the problem can only be solved through the use of a computer.

As mentioned previously, the analysis of the 2013 Practice Notices determines an element to be essential if that claim element is necessary for the successful resolution of the problem to which the application is directed. In some cases, applicants have been successful in arguing that the successful resolution of the problem requires the recited computer hardware.

  • In CA 2,735,585, the applicant argued that the invention had to be responsive to the user's inputs at the time of making a food choice decision as claimed, and that this required a large amount of nutrition data to be crunched in "real-time," which necessitated the use of a computer.12
  • CA 2,702,827, the applicant argued that training a neural network model required the use of a computer, and that the kind of neural network that could be trained by pen and paper would be trivially small, and thus unsuitable for adjusting the operation of a wellsite as claimed.13

In practice, the efficiency of a computer in performing certain tasks is what will make it indispensable to certain inventions. However, arguing on the basis of efficiency alone is usually not enough. The efficiency of executing the task must itself be essential to successful resolution of the problem.

It is worth noting that Canadian patent applicants have also been successful in arguing that the computer hardware is necessary to successfully resolve the problem for reasons other than just computational efficiency. For example:

  • In CA 2,412,184, the applicant argued that the use of the computer was essential because it resulted in vastly improved security that could not be obtained using a mere administrative scheme.14
  • In CA 2,398,508, the applicant argued that the computer was essential because serving a multitude of customers from all parts of the world with accuracy was otherwise impossible.15

#2: Emphasize that, by the language of the patent, the inventor intended for the computer elements to be essential.

The 2013 Practices Notices are silent on the effect of the patentee's intent in assessing whether an element is essential. Even so, some applicants successful in overcoming rejections for unpatentable subject matter have included arguments that under Free World Trust an element is essential where language of the patent, as purposively construed, suggests that that the patentee intended the element to be essential. The argument is usually accompanied by claim amendments that tie computer hardware into the operation of the invention. Of note, the Canadian Patent Appeal Board in Commissioners Decision 1373 (Re Application 2,312,726), held that the intent of the patentee is not a determining factor in assessing whether an element is essential.16

The success of this strategy seems to depend, in some part, on the quality of the specification. Generally, it helps to have a specification that is "replete with technical data explaining how to implement the solution" with the computer elements (see, e.g., CA 2,469,29717 response dated 2013-11-19), or one that uses numerous drawings and detailed descriptions of flowcharts to describe the computer-implemented processes (see, e.g., CA 2,506,51718 response dated 2013-11-12).

#3: Amend the preamble to repurpose the claim.

Some applicants have amended the preamble of a claim to bolster their arguments that the recited computer hardware is essential to the successful resolution of the problem, and that the patentee intended the recited computer hardware to be essential. For example:

  • In CA 2,398,508,19 the preamble which recited a "method of providing auxiliary services or goods in a computer network marketplace..." was amended to recite a "method of providing, via a computer network marketplace, auxiliary services or goods..."
  • In CA 2,702,827,20 the preamble which recited a "system for predicting subterranean formation properties of a wellsite..." was amended to recite a "system for adjusting an operation of a wellsite."

Final Words

Canadian Examiners rarely, if ever, provide reasons for withdrawing claim objections. The preceding examples and discussion are provided on the assumption that the amendments and arguments made by the applicant persuaded the Examiner. Further, issued patents and Patent Appeal Board decisions are not binding sources of precedent. Examiners at CIPO may act inconsistently with each other. For that reason, it may be expeditious to assess a prospective response strategy by conducting an Examiner interview. Finally, in deciding whether to file a new application for a computer implemented invention, one should appreciate the possibility that patent office practice may change before substantive examination of that application begins.


1. Canadian Intellectual Property Office, Manual of Patent Office Practice, available at

2. Canadian Intellectual Property Office, Practice Notices, available at main

3. Canadian Intellectual Property Office, Practice Guidance Following the Amazon FCA Decision (Mar. 8, 2013), available at

4. Canada (AG) v., Inc., [2012] 2 F.C. 459, 2011 FCA 328 (Can.).

5. Free World Trust v. Électro Santé Inc., [2000] 2 S.C.R. 1024, 2000 SCC 66 (Can.).

6. Whirlpool Corp. v. Camco Inc., [2000] 2 S.C.R. 1067, 2000 SCC 67 (Can.).

7. Canadian Intellectual Property Office, Examination Practice Respecting Purposive Construction, PN2013-02 (Mar. 8, 2013), available at cipointernet-internetopic.nsf/eng/wr03626.html

8. Patent Act, R.S.C., ch. P-4 (1985), available at

9. Id.

10. Amazon, [2012] 2 F.C. at 487.

11. Canadian Intellectual Property Office, Examination Practice Respecting Computer- Implemented Inventions, PN 2013-03 (Mar. 8, 2013), available at

12. Canadian Patent Application Serial No. 2,735,585, Response to Office Action, pp. 2-3 (Dec. 5, 2013), available at summary.htmlsummary.html

13. Canadian Patent Application Serial No. 2,702,827, Amendments/Remarks Following Examiner's Report, pp. 2-7 (June 5, 2014), available at cpd/eng/patent/2702827/summary.htmlsummary.html

14. Canadian Patent Application Serial No. 2,412,184, Response to Office Action, pp. 2-4 (Oct. 4, 2013), available at summary.htmlsummary.html

15. Canadian Patent Application Serial No. 2,398,508, Response to Requisition, pp. 1-2 (Mar. 17, 2014), available at summary.htmlsummary.html

16. Canadian Patent Application No. 2,312,726, Decision of the Commissioner of Patents, C.D. 1373 (Oct. 10, 2014), available at eng/decision/1373/summary.html

17. File History available online at patent/2469297/summary.html

18. File History available online at patent/2506517/summary.html

19. Response to Requisition, supra note 17 at 1.

20. Amendments/Remarks Following Examiner's Report supra note 15 at 36.

Previously published in the AIPLA ECLC January 2016 newsletter

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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Isi E. Caulder
Nicholas Aitken
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