Post Grant Review Cases Remain Unpopular in Japan

Trends in Japan

Between April 1, 2015 and March 8, 2016, 608 petitions for the re-introduced Post Grant Review (PGR / igi moushitate) system, which may be filed up to six months from date of issue of the patent, have been filed. This suggests a dramatic decrease from the numbers of petitions that were filed each year from the late 1990s through fiscal 2003 (in that last year, nearly 3,900 petitions were filed) when the PGR system ceased.

Meanwhile, the parallel invalidation trial (mukou shimpan) system, which was expected to absorb cases that would have been handled under the old PGR system, has failed to attract many more cases (except for the initial transitional fiscal 2004).

Post Grant Review Invalidation trial
2003 3,896 254
2015 (PGR), 2014 (invalidation) 608 (through 3/8/2016) 215

Contrast with US Practice

By way of contrast, during the United States’ fiscal year 2015 (Oct 2014-Sep 2015), the PGR system had 11 petitions filed and the Inter Partes Review system filed 1,737. Although both of these procedures are expensive, interested parties are willing to opt for them. This is likely because the alternative litigation could be much more costly in the USA, whereas in Japan the number of challenges is lower even though costs for doing so are much less.


Why are people filing so few challenges to patents in Japan? The new PGR is not an exact replication of the old system. Its documentation requirements are more demanding, nearer to invalidation trial requirements. Also, while only one examiner was needed in the old system, three must examine PGR cases under the new system, making decisions more difficult in coming.

In addition, the invalidation trial system has handed discouraging results to petitioners for invalidation. While the number of invalidation trial petitions accepted has declined slightly overall since 2003, the number of cases that led to partial or full invalidations dropped significantly in recent years (123 in 2009 to 37 in 2014).

In the end, the decreased likelihood of invalidation of a patent in whole or in part compared to previous years makes a more stable environment for those who do acquire patent rights.


Japan fiscal 2003 statistics:, p. 1.

Japan fiscal 2014/2015 statistics: (accessed April 6, 2016), sheet 11(2).

USPTO PGR and invalidation data:

* The information provided on this website is for informational purposes only and is not intended as legal advice.

Contact us

We're not around right now. But you can contact us at 215-701-6349 or 81-3-5298-6552.

Questions? We're here. Send us a message!

Click ENTER to chat