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CA2051e – The Past 10 Years of E-legal Deposit of Online Publications and Its Future

The original article published in Japanese ( )


Current Awareness

No.358 December 20, 2023



The Past 10 Years of E-legal Deposit of Online Publications and Its Future


1. Introduction

The National Diet Library (NDL) has been engaged in collection and preservation of electronic information on the Internet such as websites as well as E-books and E-journals. Among them is an online publications collecting system called the E-legal Deposit of Online Publications (hereafter “E-legal Deposit”) (1) which collects E-books and E-journals issued by those in the private sector (hereafter “privately-issued”). In July 2023, E-legal Deposit marked the tenth anniversary since its introduction. Online materials refer to electronic information published or released on the Internet and those equivalent to a book or a serial (such as E-books and E-journals). Initially, collection in this system was limited to publications that are free of charge and without technical restriction measures (DRM) (2). However, from January 2023, the scope expanded to including publications with charge or with DRM (see E2548e).

This article reviews ten years of activities of E-legal Deposit of Online Publications and discusses its challenges and future outlooks.


2. History and Overview of E-legal Deposit

2.1 Collecting Websites

NDL’s effort to collect electronic information on the Internet began with collection of websites. Since April 2010, NDL has been comprehensively collecting websites of public institutions in accordance with the National Diet Library Law as the NDL Web Archiving Project (WARP) (3) (see E1046). The NDL also selectively collects privately-issued websites with consent from respective transmitters. Websites that WARP collect include a great number of online publications, and WARP has enabled collection and preservation of online publications issued by public institutions. On the other hand, collection of privately-issued websites remains to be limited to a small portion of online publications. In order to contribute to the NDL’s mission of accumulation and use of cultural properties, a new system to collect and preserve privately-issued online publications was necessary.

2.2 Overview of E-legal Deposit

In July 2013, the amended National Diet Library Law was enforced, establishing the online publications collecting system(4) that requires publishers to deposit privately-issued online publications (see E1464). Below is an overview of the system.

2.2.1 Publications to be Collected

Among electronic information published or made available on the Internet, publications assigned a specific code (ISBN, ISSN, DOI) or circulated in a specific format (PDF, EPUB, DAISY) is subject to collection. Materials published free of charge and without DRM after July 2013, as well as those published with charge or with DRM after January 2023 are subject to deposit obligation. However, materials published before those dates are also accepted on a voluntary basis from publishers.

2.2.2 Publications Not Subject to Collection

The following cases where publications are accumulated and provided for use through other channels are excluded from the collection.

  • Those reported as having the same edition as already deposited paper-based books or journals and confirmed by the NDL
  • Those included in websites collected by WARP
  • Those intended for long-term use and unerasable (publications in repositories of academic and research institutions) (5)

Regarding the third point, publications collected in repositories managed by organizations consisted of commercial firms are to be excluded from deposit obligation in case the NDL confirms that prescribed requirements are met, and a memorandum of understanding is concluded with the operator of the repository. Currently, publications collected in the “Digital Publishers Federation of Japan Institutional Repository” are excluded for this condition. This is preservation project of E-book data by General Incorporated Association Digital Publishers Federation of Japan(6).

2.2.3 Method of Collection

There are three collection methods: “automatic crawling” in which the NDL collects files from websites releasing online publications, “transmission” in which the supplier (publisher) logs into the NDL system and uploads files of online publications, and “sending” in which files are stored on DVD-R and mailed to the NDL in case collection cannot be completed in either of the first two methods. Those with DRM are to be collected as files in a DRM-free state.

2.2.4 Provision for Use

Collected online publications are made public in the NDL Digital Collections (see E2604)(7) after adding metadata. In principle, browsing is limited to within the NDL facilities. However, publications are made available on the Internet only when permission is obtained from the rights holders. Part of the online publications included in the websites collected by WARP are extracted from WARP and registered in the Digital Collections.

Search for collected online publications is possible not only through the Digital Collections but also through the NDL Online(8). Furthermore, NDL Search(9) enables integrated search across excluded publications such as those collected in repositories.


3. Collection Achievements and Challenges

3.1 From the Start of the System to the Expanding the Scope of Collection

Because deposits were slow at the beginning, from 2013 to 2016, we conducted a search of online publications posted on websites of academic associations and private companies and requested deposits. As a result, we collected many journals, newsletters and bulletins of academic associations, as well as business reports, shareholder newsletters, and technical reports of private companies. Since many of them are published on a regular basis, we have continued to collect them to date. In 2018, we began accepting academic association journals and other publications that have shifted their format from paper to online, and with charge or with DRM, from publishers on a voluntary basis. Furthermore, since January 2023 when deposit of publications with charge or with DRM became an obligation, we have been collecting diverse materials published by commercial publishers (e.g. specialized books, practical books, light novels, and children’s books).

3.2 Collection Achievements (As of the end of September 2023)

Cumulative numbers of online publications collected through the E-legal Deposit or extracted from WARP are presented in the table(10). The NDL uses the number of metadata (bibliography) as the collection statistics of online publications. However, granularity of generation differs from that of paper-based publications. For example, metadata is created with articles as the unit in case the publications are distributed as article/paper-based files. As such, in order to enable comparison with collection statistics of paper-based books and journals, the table also contains, as reference, the number of items that correspond to “physical unit of a book” if the material had been published paper-based. The number presented for publications with charge is the number of collections after January 2023. Extraction from WARP includes online publications of public institutions.


Table: Number of Collected Online Publications (As of the end of September 2023)
E-legal Deposit Extracted from WARP
Of Which Publications with Charge
Number of Metadata 118,267 cases 752 cases 779,714 cases
Of Which Article as Unit 77,955 cases 8 cases 270,483 cases
[Reference] Number of Physical Items 38,520 items 728 items 501,320 items

Source: Internal statistics(11)

Among publications with charge, 337 were excluded from deposit obligation for being the same edition as already deposited paper-based books. Among publications collected in Digital Publishers Federation of Japan Institutional Repository, 12,429 items met the exclusion requirement.

3.3 Challenges

This section discusses three challenges and their future prospects.

Challenge 1: Improving rules for determining collection targets and creating metadata

Online publications have unique characteristics such as non-uniform units of distribution (books, chapters, articles) as well as frequent revisions. As a result, we face unprecedented situations on a daily basis in determining the eligibility of the publication for collection and in generating metadata. There is a need to establish reasonable operation rules based on the characteristics of online publications. In pursuit of this, we are engaged in thorough examination of responses in daily operations, accumulating examples and know-hows.

Challenge 2: Grasping the number of publications of online publications with charge and requesting deposits

Since January 2023, the NDL has collected a total of approximately 13,500 items of online publications with charge. This includes those collected through the E-legal Deposit and those excluded from deposit obligations for being the same edition as already deposited paper-based publication or for inclusion in repositories. On the other hand, the total number of online materials with charge published after January 2023 is difficult to capture with no available statistics. However, we find approximately 26,000 items only by looking at publication information of E-books provided by the Japan Publication Registry Office (JPRO) (12). This can be searched in the NDL Search. We are aware of many uncollected publications. We intend to make the effort to grasp uncollected publications by cross-checking with publication information and making deposit requests to publishers. (The two data in this paragraph are both as of the end of September 2023).

Challenge 3: Strengthening Cooperation with Repositories of Other Institutions

One key aspect of E-legal Deposit is its aim for comprehensive collection and preservation through sharing and cooperation with WARP and other institutional repositories. It is therefore necessary to realize rational and efficient collection and preservation while eliminating omissions and duplications.

It is also important to enable those publications excluded as out of scope in this system to be identified through integrated search. The NDL plans to integrate and renew the NDL Online and the NDL Search in January 2024. In addition to its use at the NDL, we plan to enhance the navigation function to repositories of other institutions and E-book sales sites.


4. Conclusion

With an expansion of scope since January 2023, targeted publications for the E-legal Deposit have largely increased and diversified. The system faces the need to urgently respond to challenges discussed in the earlier section, and the department in charge is making intense effort. We ask for your understanding of the purpose of the system and for your cooperation in collecting publications. Please follow the NDL’s effort to collect and preserve online publications to pass them on to future generations.


* References are not translated and remain in Japanese language.

(1) オンライン資料収集制度(eデポ)., (referenced 2023-10-02).
(2) DRM refers to measures that restrict or limit at least one of the following: long-term preservation, duplication for preservation, and viewing on multiple devices.
納本制度審議会. 答申 オンライン資料の制度収集を行うに当たって補償すべき費用の内容について. 2021, p. 2-3., (referenced 2023-10-02).
(3) 国立国会図書館インターネット資料収集保存事業., (referenced 2023-10-02).
Prior to 2010, the National Diet Library had been engaged in permission-based collection of websites.
(4) 平田紀子. 国立国会図書館のオンライン資料収集制度について. 図書館雑誌. 2023, 117, p. 390-391.
(5) Excluded from the scope of collection are publications collected in J-STAGE and in institutional repositories that provide data to Institutional Repositories Database (IRDB). Japan Science and Technology Agency (JST) and the NDL has confirmed that publications collected in J-STAGE, managed by JST, are to be excluded based on The National Diet Library Law Article 25 Section 3. As such, academic associations that register publications to J-STAGE have no deposit obligations to the E-legal Deposit of Online Publications. Publications collected by institutional repositories providing data to IRDB are excluded based on the National Diet Library Law Article 25 Section 3 or Article 25 Section 4, depending on the attribution of respective institutions.
J-STAGE., (referenced 2023-10-02).
IRDB., (referenced 2023-10-02).
(6) 一般社団法人デジタル出版者連盟., (referenced 2023-10-02).
(7) 国立国会図書館デジタルコレクション., (referenced 2023-10-02).
(8) 国立国会図書館オンライン.!/, (referenced 2023-10-02).
(9) 国立国会図書館サーチ., (referenced 2023-10-02).
(10) In addition to these items, “E-books and E-journals” of the NDL Digital Collections include academic articles transferred from the National Institute of Informatics Electronic Library Service (NII-ELS) in FY 2017-2018 due to its closure (approximately 600,000 articles), as well as NDL publications (approximately 10,000 items).
(11) Metadata of online publications consist of up to three levels. From the top, these are title-level, volume-level, and article-level. The numbers presented as “Of Which Article as Unit” in this table refer to the numbers of metadata at article-level. The “number of physical items” presented as a reference is the sum of: 1) the number of metadata consisted only of title-level and without volume- or article-level (as in the case of monographs), and 2) the number of volume-level metadata when multiple volume numbers attached under a single title (as in the case of journals).
(12) A system for distributing publishing information provided by publishers to bookstores and distributors. The system is managed by General Incorporated Association Japan Publishing Organization for Information Infrastructure Development (JPO). As of July 2021, approximately 2,000 publishers are registered with JPO.

[Accepted: 2023-11-07]

Written by Hara Satoko
Digital Library Division
Kansai-kan of the National Diet Library
Translated by Okada Aya