I'm in an antitrust law class and we are talking about the competitiveness of patents. Several cases and economists have referred to both one-way and two-way blocking patents.

I fully understand how a patent can be one way blocking. I.e. a base patent then an improvement patent on that same technology, therefore base patent will block the practice of the improvement. However, the improvement does not block the practice of the base patent so this is only one way blocking.

But how can two patents ever be two way blocking? Wouldn't their claims have to be identical? Can someone give me an example of two way blocking?

I've seen several economics papers stating one and two way and they give an example of one way but not two way. My assumption is that a two way blocking patent would be an improvement so essential to a consumer they wouldn't accept the base product without it.

1 Answer 1


By doing a little Google search and based on my everyday work as well, I have come down to this: a two-way blocking position (and not patent) is a situation where there are two patents which cannot be used without infringing one another. For example, a patent for a chemical compound and a patent for a certain crystalline form of the chemical compound (which is the most stable and therefore more preferable). Each patent holder needs a licence from the other one to produce this chemical compound in said crystalline form. And everybody else would be infringing both of those patents.

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