Monthly Archive: May 2019

New Japanese Imperial Era: Retrieval of Japanese Patent Information

On 30th April 2019 Emperor Akihito of Japan abdicated and his son Emperor Naruhito acceded to the Chrysanthemum Throne on 1st May.  This marked the end of the Imperial Heisei era and the beginning of the Reiwa era.

In this post I look at how the Japanese Imperial eras define the calendar dates and passage of time in many Japanese documents, including (in previous years) patents and patent applications.

Although the Japanese Patent Office started using Gregorian calendar years in 2000 and no longer uses the Imperial calendar, searching, retrieving and analysing older Japanese patents and applications still requires knowledge of the Imperial calendar system.


A History of the Japanese Patent Numbering System

Many aspects of Japanese society mark time by the Imperial calendar – the eras defined by the reigns of individual emperors.  Japan first adopted the Gregorian calendar in 1873, however, the extent of usage of the two systems varies.  The Japanese Patent Office, as an example, used the Imperial system up until 2000.

Within the Imperial calendar, one era ends and a new era starts with the accession of a new emperor.  The remainder of the corresponding Gregorian year then represents the first year of the new Imperial era.  Full subsequent Imperial years are then counted in synchrony with the Gregorian calendar, until the accession of a new emperor and the beginning of a new era.

To illustrate this, let’s look at the last three emperors of Japan in the figure below.



Wikipedia. (2019, May 25). “Akihito”. Retrieved May 26, 2019, from:

Wikipedia. (2019, May 26). “Hirohito”. Retrieved May 26, 2019, from:

Wikipedia. (2019, May 26). “Naruhito”. Retrieved May 26, 2019, from:


Emperor Hirohito came to the Chrysanthemum Throne on 25th December 1926, and his era was known as Showa.  When he died on 7th January 1989, Emperor Akihito acceded to the Chrysanthemum Throne, and the Heisei era began.  Emperor Akihito abdicated on 30th April 2019, and Emperor Naruhito acceded, thus beginning the Reiwa era.

1926 is the first year of the Showa era (S1), 1927 is the second Showa year (S2) etc.  1976 (Showa 51) is when the Patent Abstracts of Japan database began (containing bibliographic information of published unexamined patent applications).  The Showa era ended in 1989.  This year is Showa 64 up until the accession of the new emperor, when it becomes the first year of the Heisei era (H1).  Documents published in that year will have either a Showa 64 or Heisei 1 designation depending upon the exact date of publication.

Similarly, Heisei 2 is 1990 and so on through out the reign of Emperor Akihito.  The Japanese Patent Office (JPO) used the Imperial calendar up until 2000, when it then switched to using the Gregorian calendar for dates assigned to new patent publications.  Thus, the last documents published by the JPO using the Imperial calendar system were published in 1999 (Heisei 11).

The Heisei era ended on 30th April 2019 (Heisei 31) and the first year of the Reiwa era began the following day.


Types of Japanese Patent Documents

There are three main types of national Japanese patent documents.

The first are Kokai, or the publication of an unexamined patent application.  These are usually identified with a kind code “A”.

The second (relevant to patents prosecuted prior to 1996) are Kokoku, or the publication of an examined patent application.  These are typically identified with a kind code “B”.  After 1996, Japanese patent law changed and Kokoku documents were no longer published.

The third are Toroku, or the publication of a granted patent.  These are identified with a kind code “B”.


Retrieval of Japanese Patent Documents

When identifying, searching and retrieving Japanese patent documents, it is necessary to have an understanding of the numbering formats of the different document types discussed above.  The formats of each of three document types are illustrated in the following figure.


Toroku documents (on the right of the figure) are the simplest, having a two-letter country code “JP”, a seven-digit document number, and the kind code “B” suffix.

Kokai and Kokoku are a little more complex.

Kokoku documents (centre) have a two-letter country “JP”, a two-digit Imperial year code (corresponding to the Imperial era discussed above), followed by a six-digit document number, and the kind code “B” suffix.

Prior to 2000, Kokai documents (left of the figure) followed the same format as Kokoku documents, except that they have an “A” kind code.  From 2000 onwards, the two-digit Imperial year code was replaced with a four-digit Gregorian year – the other parts of the number format remained the same.

When working with Japanese patent documents, it is important to accurately identify the document concerned by careful consideration of the procedural stage and the year of publication, which may not be immediately obvious if one is not familiar with the various date formats described in this post.

Additionally, care should be taken to understand how specific databases require publication numbers to be entered.  If not, there is a risk of falsely assuming a document is not available in the database, when in fact it is, or worst, end up retrieving the wrong document.


Avoiding Pitfalls

Common pitfalls to avoid include determining whether or not the database you are using requires additional information such as an “S” or “H” within the publication number to distinguish the Showa and Heisei eras.  Some databases are indexed this way.

In such databases, JP54123456A would be searched as JPS54123456A, and JP10123456B would be searched as JPH10123456B.  Omitting this additional information can result in a document not being retrieved when it is actually available.

Further, documents from the early Heisei era can sometimes be presented with the leading zeros of the Imperial year omitted.  Thus, JP01123456 may come to you initially as JP1123456, which can easily be misinterpreted as a Toroku (granted) document rather than a Kokai (published application).

It is important to treat such documents carefully by first identifying the procedural stage you expect, and as necessary applying the right imperial year code to ensure the correct document is retrieved and worked with.

It is always advisable to double-check the documents you are working with by crossing-checking against other information such as application and priority data, document title, or other published family members.

Alistair Curson



European Patent Office. (2019, May 14). “Numbering system – Japan”. Retrieved May 26, 2019, from:

Japan Patent Office. “Searching for Patents, Utility Models, Designs, Trademarks”. Retrieved May 26, 2019, from:

Korteman J. (2019, April 01). “How to Read a Japanese Calendar”. Notes of Nomads. Retrieved May 03, 2019, from:

Reynolds I, Mori K. (2019, May 01). “Japan’s New Emperor Naruhito Ascends World’s Oldest Monarchy”. Bloomberg. Retrieved May 03, 2019, from:

Wikipedia. (2019, May 25). “Akihito”. Retrieved May 26, 2019, from:

Wikipedia. (2019, May 26). “Hirohito”. Retrieved May 26, 2019, from:

Wikipedia. (2019, May 26). “Naruhito”. Retrieved May 26, 2019, from:

World Intellectual Property Organisation: Handbook on Industrial Property Information and Documentation. (2005, December). “Presentation of Application Numbers”. Retrieved May 03, 2019, from:

WIPO AI-Based Brand Search Database

On the 1st of April, the World Intellectual Property Organisation (WIPO) announced the launch of its new artificial intelligence (AI)-based image search tool for searching trade marks and brands.

This new tool makes it even easier for small business owners to make meaningful trade mark searches, for example, to determine the registrability of a new mark and to make strategic decisions about expanding their brand into new markets and geographies.

The AI search technology has been integrated into the WIPO Global Brand Database, which is available for free at this link:

There are also useful video tutorials on this page to help you get started.


Principles of Trademark Identity and Similarity

The purpose of a trade mark is to act as a “badge of origin”, distinguishing your goods and services from those of other businesses within your industry.  They serve to minimise consumer confusion and protect the consumer from deception.

Two of the tests which may lead to the refusal or successful opposition of a registered trade mark are whether the signs are identical or are similar to other existing marks.

An identical mark reproduces, without any modification or addition, all the elements that make up another mark.  When viewed in their entirety, any differences between the two marks would go unnoticed by the average consumer, such that they are effectively indistinguishable.

Marks are considered similar when, based upon the overall impression they give, their visual, aural and conceptual features are such that there is a high chance that the average consumer would be confused by the two marks.  They would unable to easily distinguish which mark was which, and hence which business or brand was associated with either of the two marks.

A trade mark search can help begin to address these questions.  When appropriately placed in the context of the relevant goods and services your business intends to operate in, as well as the goods and services of the owners of the marks your search finds, it can help ensure a suitable mark is chosen that is distinctive for your business.


Benefits of the New Search System

Image search technology has progressed massively over recent years and utilises a variety of methods to find and retrieve images.  These include text-based indexing of filenames and metadata, as well as basic image analysis.

Within the trade mark searching space, previous image search engines would often determine similarity between trade mark images by identifying and comparing factual parameters such as shapes and colours.

Artificial intelligence takes this type of image search to a new level.  AI is developing rapidly and becoming more and more engrained in every aspect of life, society and business, in areas as diverse as healthcare, retail, manufacturing and sport.  WIPO is now applying AI to many of their offerings, including trade mark searching.

In their brand search database, WIPO’s new AI-based technology improves on existing image search technology by using deep machine learning to identify combinations of concepts, rather than relying solely upon the more factual aspects of an image.

The result is a search engine that greatly improves the ability of individuals and businesses to conduct effective, basic trade mark searches as part of their brand development and marketing strategies.

Alistair Curson



Bainbridge D. (2012). Intellectual Property, 9th edn, Pearson Education Limited, Harlow, England.

LTJ Diffusion v Sadas Vertbaudet SA [2003] FSR 34.

New Zealand Trade Marks Act 2002, s25. Retrieved May 11, 2019, from:

Sabel BV v Puma AG, Rudolf Dassler Sport [1998] RPC 199.

SAS. “Artificial Intelligence: What It Is and Why It Matters”. Retrieved May 12, 2019, from:

Si S. (2019, March 23). “The Best Visual Search Engines You Can Use On Your Browser”. Retrieved May 12, 2019, from:

Smith M. (2012, January 12). “How Image Search Engines Work”. Retrieved May 12, 2019, from:

United Kingdom Trade Marks Act 1994, s5. Retrieved May 11, 2019, from:

World Intellectual Property Organisation. (2019, April 01). “WIPO Launches State-of-the-Art Artificial Intelligence-Based Image Search Tool for Brands”. Retrieved May 10, 2019, from: