Analysis of Reference Books in Japanese Public Libraries Regarding
their Number of Holdings, Frequency of Use, and Price
Nozomi Nomura
Graduate School of Library, Information and Media Studies, University of Tsukuba
1-2, Kasuga, Tsukuba, Ibaraki, 305-8550, Japannozomi@slis.tsukuba.ac.jp
Shunsuke Arai
Graduate School of Library, Information and Media Studies, University of Tsukuba
1-2, Kasuga, Tsukuba, Ibaraki, 305-8550, Japansyun0201@gmail.com
Keita Tsuji
Faculty of Library, Information and Media Science, University of Tsukuba
1-2, Kasuga, Tsukuba, Ibaraki, 305-8550, Japankeita@slis.tsukuba.ac.jp
Keywords: reference books, reference services, Japanese public libraries

Abstracts
The purpose of this study is to identify important reference books in Japanese public libraries
and provide useful information to librarians who are considering purchasing them. We
investigated the following three points and compiled lists of reference books: (1) whichreference books are held in most Japanese public libraries; (2) which reference books appear
most frequently in the reference records; and (3) which reference books are cost-effective
considering their price and frequency of use. The number of our sample reference books is 77
and the number of public libraries is 634. We used Calil API, which can perform cross-library
searches and OPAC of each library to investigate holdings. As for reference records, we usedthose recorded in the Collaborative Reference Database maintained by the National Diet Libraryof Japan. We assume that the number of appearances of a reference book in the reference
records represents its frequency of use in libraries. It was found that (1) Encyclopedia of Newsin the Meiji Era (Meiji News Jiten) and Chronological Table of Japan in the Modern Period(Kindai Nihon Sogo Nenpyo) were held by most libraries, (2) Encyclopedia of Japanese People(Nihon Jinmei Daijiten) and Encyclopedia of Modern Japanese Literature (Nihon Kindai
Bungaku Daijiten) were the most frequently used, and (3) Encyclopedia of Modern Japanese
Literature (Nihon Kindai Bungaku Daijiten) and Encyclopedia of Westerners (Rainichi Seyo
Jinmei Jiten) were the most cost-effective. Libraries that do not hold these books should
consider purchasing them.

1. Introduction
Reference books are important for reference services (Nagasawa, 1995); however, it has been
pointed out that Japanese public libraries do not hold enough reference books (MEXT, 2014;
MEXT, 2006). There are some information sources for choosing reference books such as
guidebooks, magazines, and websites such as Research Navi (http://rnavi.ndl.go.jp/rnavi/).
However, the reference books listed in these sources seem to be chosen empirically (for instance,
Research Navi introduces reference tools that Japanese National Diet Library staff regarded as
useful without showing the objective reasons). Sources and studies that recommend reference
books based on objective and quantitative analysis are few.
Against this background, we try to identify reference books that are useful and effectivefrom several viewpoints. More specifically, we investigated the following three points andcompiled lists of reference books: (1) reference books held in most Japanese public libraries; (2)reference books appearing most frequently in the reference records; and (3) which reference
books are cost-effective considering their price and frequency of use. We assume that the
number of appearances of a reference book in the reference records represents its frequency ofuse in libraries. Furthermore, we assume that reference books that are held in many libraries,
used many times, and comparatively inexpensive are useful, effective, and in this sense,
important reference books. The number of our sample reference books is 77 and the number ofpublic libraries is 634.
As for (1), we used Calil API and OPAC of libraries. Calil API can perform cross-library
searches among Japanese public, university, and special libraries, which enables us to findlibraries that hold the sample reference books efficiently (we used OPAC when Calil failed tofind the books as we will mention later). As for (2), we used reference records in the
Collaborative Reference Database maintained by the Japanese National Diet Library. As for (3),
we identified the prices of the reference books based on various information sources andregarded that “the frequency of use of a reference book” divided by “its price” represents thecost-effectiveness of that book.

2. Related Studies
Sugie (2007) investigated five libraries in the Kanto area to determine which health sciencereference books are held. Her focus was limited to the health science field. Mabe (2011) focusedon the availability of reference books that were used in the reference records and investigated(1) which reference books can be purchased, (2) which reference books can be substituted byother media, and (3) which reference books can be borrowed from other libraries. However, his
focus was limited to Japanese prefectural libraries and it is not clear which reference books areheld in other kinds of libraries such as city libraries.
Mabe et al. (2011) and Yoshida (2014) investigated reference books used in actualreference works. Mabe et al. (2011) investigated reference records in the Collaborative
Reference Database and clarified which reference books appeared in them. Yoshida (2014)
conducted a questionnaire survey with participants of training in reference services held by the
Library Association in Aichi Prefecture. She asked which reference books and reference tools on
the Internet were often used.
As mentioned above, there are some studies on reference books; however, few studies havebeen conducted on reference books held in Japanese public libraries in general.

3. Sample Data
In this section, we explain the sample reference books, public libraries, and reference records
we investigated in this study.
3.1. Sample reference books
We randomly selected sample reference books from those listed in Japanese Reference Books:
How to Select and Use (Nagasawa et al., 2013). The reason we chose this book is that Masao
Nagasawa, the book’s first author, is a representative researcher of reference services and thebook is very popular among Japanese librarians. In addition, Japanese Reference Books: How to
Select and Use is the newest guidebook on reference books in Japan as of 2015. There areseveral guidebooks from which to select sample reference books (Yoshida, 2006); however, we
will reserve these options for future research. Japanese Reference Books: How to Select and Use
consists of eight chapters; we randomly chose 10 reference books from each chapter ranging
from chapter 1 to 8. With ten reference books chosen from eight chapters, we ended up with 77
sample reference books because only seven reference books are shown in Chapter 1.
3.2. Sample libraries and municipalities
We investigated Japanese prefectural libraries, special ward libraries, city libraries, town
libraries, and village libraries. To judge whether they hold specific reference books, we used
Calil API and OPAC of each library. Calil API can perform cross-library searches among
Japanese libraries, which enables us to find libraries that hold the sample reference books
efficiently (as of March 9, 2015, it can search 6,654 libraries) (Calil, 2015). It can retrieve books
in most, though not all, Japanese libraries. Therefore, we chose sample libraries from those that
Calil API can handle. The numbers of our sample public libraries and the municipalities (such asprefectures, special wards, cities, towns, and villages) they belong to are shown in
Table 1. As for prefectural, special ward, and village libraries, they are all that Calil can retrieve(i.e., complete enumeration). As for the city and town libraries, we randomly selected 206 and75 sample libraries from those that Calil can retrieve.
Table 1. Number of Sample Municipalities and Libraries
The Number of
The Kinds of

The Number ofSampleLibraries

Sample Libraries
Municipalities

Prefectural libraries

47

59

Special ward libraries

23

246

City libraries

50

206

Town libraries

50

75

Village libraries

41

48

211

634

Total

3.3. Sample reference records
In this study, we investigated reference records in the Collaborative Reference Database(https://crd.ndl.go.jp/reference/) maintained by the Japanese National Diet Library and noted
how many times our sample reference books were used in the reference records. The
Collaborative Reference Database is a database that accumulates reference records reported byvarious Japanese libraries, such as public and university libraries. As of March 3, 2015, thenumber of participant libraries was 650. We collected 62,330 reference records on March 19,
2013 and used these for our investigation.

4. Methodology
In this section, we will explain our methods: (1) to check whether or not the libraries hold thebooks; (2) to count the number of appearances of the reference book in the reference records;(3) to investigate the price of the reference book.
4.1. How to check whether or not the libraries hold the books
We used the following three methods to examine which reference books Japanese public
libraries held: (1) by ISBN via Calil API; (2) by ISBN via each library’s OPAC; and (3) by titles
via OPAC. With these three methods, we expect to minimize the error regarding libraries that do
not hold the books despite the fact that they do in fact have them. We conducted these retrievalsfrom April 17, 2014 to November 27, 2014.
4.1.1. Retrieving books by Calil API based on ISBN
Because Calil API only allows us to search books by ISBN, we first retrieved the sample
reference books by ISBN. There are some reference book titles that are assigned multiple ISBNs.
For instance, A New Version of Comprehensive National Poems (Shinpen Kokka Taikan)
consists of ten volumes and an ISBN is assigned to each volume. In such cases, we used three
ISBNs as follows. First, we defined n as a smallest integer that is larger than N/2, where N is thetotal number of volumes of a reference book. For instance, if a reference book consists of ninevolumes, n is defined as 5 (which is larger than 9/2=4.5). We used three ISBNs of volumes No.
n-1, No. n, and No. n+1. As for the yearbook that still continues to be published, we used thethree ISBNs of the three latest volumes. We regarded the reference book as being held if one ofthese three volumes was held. The reason we did not use all the ISBNs of all the volumes wasjust to reduce investigation costs.
4.1.2. Retrieving books by OPAC based on ISBN
Unfortunately, Calil API sometimes fails to find books. Therefore, we used each library’s OPAC
when Calil API reported that the books were not held in the library. We retrieved sample

reference books by OPAC based on their ISBN.
4.1.3. Retrieving books by OPAC based on titles
Some OPACs do not allow an ISBN search, and others sometimes fail to find books through an
ISBN search. Therefore, we also retrieved books by their titles. Since a title search is more
complicated than an ISBN search, we will explain in detail below how we retrieved books bytheir titles. First, we used MeCab, the Japanese morphological analyzer, and decomposed thetitles into words and POS-tags. We then selected the following nine combinations of nouns intitles and used them as search keywords: (1) the first four nouns; (2) the first three nouns andthe last noun; (3) the first two nouns and the last two nouns; (4) the first noun and the last three
nouns; (5) the last four nouns; (6) the first three nouns; (7) the first two nouns and the last noun;(8) the first noun and the last two nouns; and (9) the last three nouns. If the title was too short to
extract four nouns, we tried all the noun combinations as search keywords. In addition, we used
the titles of the reference books directly as search keywords without using MeCab.
4.2. Number of times used in the reference records
As we mentioned earlier, we investigated the reference records in the Collaborative Reference
Database and noted how many times our sample reference books were used in the reference
records. We counted the number of reference books being used just by a simple string match
between the titles and description of the records. Therefore, the counts may be slightly smaller
than the actual counts of being used because our simple string match cannot find titles that areslightly modified in the records.
4.3. Price and cost-effectiveness of reference books
We assume that the values “number of times that the reference books were used in the reference
records” divided by “their price” represent their cost-effectiveness (henceforth we call this valueNP). We investigated which reference books are cost-effective and how many libraries holdthem.
To find the prices of reference books, we used the following four methods: (1) using
information on the Internet; (2) using reference books; (3) checking actual sample reference
books; and (4) using the catalogs of the publishers. As for (1), we used OPAC of the Japanese
National Diet Library (https://ndlopac.ndl.go.jp) and Books.or.jp (http://www.books.or.jp/)
maintained by the Japan Book Publishers Association. If we could not find the prices by these
two websites, (2) we checked Yearbook of Publication (Shuppan Nenkan) and Catalog of
Research and Study Reference Books (Chosa Kenkyu Sankotosho Mokuroku) to find their prices.
If we could not find them, we used methods (3) and (4).
In this study, we used the price excluding consumption tax. In the case of multi-volume
sample reference books, we investigated the price of all the volumes of the sample reference
books. In the case of reference books such as yearbooks, we investigated the prices of reference
books that have been published over the past two decades.

5. Results
5.1. Reference books that many municipalities holdSome municipalities have multiple public libraries. For instance, 50 cities have 206 libraries intotal as we showed inTable 1. In such municipalities, public libraries sometimes share their collections due to limited
budget. In this case, we cannot blame library A for not holding reference book X if library B in
the same municipality holds it. Based on this idea, we investigated which reference books areheld in each municipality (i.e., not on a libraries basis). Table 2 shows the top 20 reference
books that most municipalities hold.
We can see in Table 2, for instance, that 174 municipalities have Encyclopedia of News in
the Meiji Era (Meiji News Jiten) and the ratio is 82.5%, which is the largest ratio among sample
reference books. Chronological Table of Japan in the Modern Period (Kindai Nihon Sogo
Nenpyo) is held in 75.4% of sample municipalities, which is the second-largest ratio among
sample reference books.
The results shown in Table 2 are those on a municipalities basis; however, results on alibraries basis were not significantly different (i.e., reference books listed in Table 2 were heldin many libraries).

5.2. Reference books that are used many times in the reference records
We investigated how many times our sample reference books were used in the reference records.
Table 3 shows the top 20 reference books that were most frequently used. Encyclopedia ofJapanese People (Nihon Jinmei Daijiten) was used 66 times in the reference records, which was
the largest number among the sample reference books. Encyclopedia of Modern Japanese
Literature (Nihon Kindai Bungaku Daijiten) was used 42 times in the reference records, which
was the second-largest amount among sample reference books.
Table 2. Top 20 Reference Books Held in Many Municipalities
Prefectu Special
Municip
Cities Towns Villages
Ratio
res
Wards
alities
1 Encyclopedia of News in the Meiji Era
47
23
45
37
22
174 82.5%
2 Chronological Table of Japan in the Modern Period
47
23
42
35
12
159 75.4%
3 Techno Atlas of Japan
45
22
40
32
19
158 74.9%
4 Encyclopedia of Modern Japanese Literature
47
23
43
27
6
146 69.2%
5 Dictionary of Direct Words in Japan
47
23
38
26
10
144 68.2%
6 Chronological Table of World History
47
21
38
21
8
135 64.0%
7 Encyclopedia of Musician
47
23
36
21
7
134 63.5%
7 Times Wrold Map: Live Atlas
44
20
33
19
18
134 63.5%
7 Encyclopedia of Japanese People
46
23
39
21
5
134 63.5%
10 Yearbook of Literature
46
23
35
22
7
133 63.0%
11 Series of Full Information
47
23
36
24
2
132 62.6%
12 Dictionary of Foreigner in the Modern Era
47
23
32
23
3
128 60.7%
13 Dictionary of Synonym
46
23
39
11
7
126 59.7%
14 Illustrated Dictionary of Fossil
43
18
32
22
9
124 58.8%
14 A New Version of Comprehensive National Poems
47
22
37
14
4
124 58.8%
16 Encyclopedia of Current Law
43
20
29
20
8
120 56.9%
16 Japanese Reference Book
47
23
36
11
3
120 56.9%
18 Dictionary of Difficult Reading of a Kanji
47
23
32
15
2
119 56.4%
18 Encyclopedia of Cultural Anthropology
47
23
35
11
3
119 56.4%
20 Illustrated Fishes in Colour Revised Edition
43
23
30
15
6
117 55.5%
Reference Books' Titles

Table 3. Top 20 Reference Books That Were Most Frequently Used in the Reference Records

Reference Books' Titles

1 Encyclopedia of Japanese People
2 Encyclopedia of Modern Japanese Literature
3 A New Version of Comprehensive National Poems
4 Encyclopedia of News in the Meiji Era
5 Reference Dictionary of Foreigner
6 Series of Pandect of Modern Japanese Literary
7 Series of Full Information
8 The Complication Pandect of The State of a Country in Showa Era
9 Encyclopedia for place names of Great Japan
10 Catalog of Oya Soichi Library
10 Dictionary of Buddhist Japanese People
12 Yearbook of Literature
13 Dictionary of Foreigner in the Modern Era
13 Encyclopedia of Westerners
13 Catalog of Translation Book
16 Encyclopedia of Akita
17 The Genealogies of the Houses of biographical dictionary in History of Japan
18 Japan Newspaper Annual
19 The New Grove Dictionary of Music and Musicians
20 Encyclopedia of Hyogo

Number of
Being Used
Prefectur Special
in thees
Wards
Reference
Records
66
42
30
25
23
20
19
17
16
14
14
13
12
12
12
11
10
9
8
7

46
47
47
47
47
47
47
39
47
47
39
46
47
47
47
31
44
46
16
38

23
23
22
23
22
23
23
17
23
21
18
23
23
23
23
4
21
17
2
5

Cities

39
43
37
45
20
29
36
11
29
11
12
35
32
27
19
5
25
12
1
7

Towns

Villages

Municip
alities

21
27
14
37
8
13
24
1
8
4
8
22
23
14
11
1
19
2
0
3

5
6
4
22
1
1
2
1
1
0
1
7
3
2
0
1
3
1
0
0

134
146
124
174
98
113
132
69
108
83
78
133
128
113
100
42
112
78
19
53

Ratio

63.5%
69.2%
58.8%
82.5%
46.4%
53.6%
62.6%
32.7%
51.2%
39.3%
37.0%
63.0%
60.7%
53.6%
47.4%
19.9%
53.1%
37.0%
9.0%
25.1%

As we previously mentioned, the records of the Collaborative Reference Database areregistered by various Japanese libraries. The number of records each library registered varies.
Some registered many and others few (Tsutsumi et al., 2011). Therefore, one particular librarymight have registered a particular reference book many times in the records. In such cases, highfrequency in the records does not represent general (universal) importance to libraries as awhole. Based on this idea, we focused on the frequently used reference books and investigatedwhich libraries registered them in the reference records. Saitama Prefectural Kuki Libraryregistered 23 times concerning the most registered reference book Encyclopedia of Japanese
People (n=66 times). The Tokyo Metropolitan Central Library on the other hand registered thesecond highest frequency of use for the same book but it was just for five time only. Therefore,
the high frequency of Encyclopedia of Japanese People can be attributed to various libraries,
not a specific library (i.e., other libraries registered it 38 (=66 minus 23 minus 5) times in thereference records). Encyclopedia of Modern Japanese Literature whose frequency was 42 was
the same. The library that registered it the most was Saitama Prefectural Kuki Library and thenumber was just six. On the other hand, we found two reference books whose frequency could
be attributed to specific libraries, i.e. The New Grove Dictionary of Music and Musicians andEncyclopedia of Akita. The former was used eight times in the reference records and was
registered solely by Toho Gakuen School of Music Library. The latter was used 11 times in thereference records and was registered by Akita Prefectural Library eight times. The ratio is72.7% (=8/11). However, such ratios were less than 50% concerning all the libraries that
registered the reference books other than these two. Therefore, we believe that the frequency inthe reference records represents the importance (or usefulness) of the reference book for many
libraries not a specific library.
5.3. Which reference books are cost-effective
Table 4 shows the top 20 reference books whose NPs were the largest. The NP of Encyclopediaof Modern Japanese Literature (Nihon Kindai Bungaku Daijiten) was 0.003500, which was thelargest among the sample reference books. The value of Encyclopedia of Westerners (Rainichi
Seyo Jinmei Jiten) was 0.002575, which was the second largest among sample reference books.
Table 4. Top 20 Cost-effective Reference Books
Reference Books' Titles

1 Encyclopedia of Modern Japanese Literature
2 Encyclopedia of Westerners
3 The Genealogies of the Houses of biographical dictionary in History of Japan
4 Encyclopedia of Japanese People
5 Dictionary of Buddhist Japanese People
6 Catalog of Translated Literary Work in Meiji, Taisho, and Showa Era
7 Dictionary of Direct Words in Japan
8 Handbook of History of Japan
9 Encyclopedia of Akita
10 Encyclopedia of Nigata
11 Chronological Table of Japan in the Modern Period
12 World History Atlas
13 Dictionary of Foreigner in the Modern Era
13 Encyclopedia of Cultural Anthropology
13 Chijin Shokan Dictionary of Astronomy
16 Techno Atlas of Japan
17 Dictionary of Difficult Reading of a Kanji
18 Yearbook of Literature
19 Dictionary of Secret Language
19 Encyclopedia of Hyogo

NP

0.003500
0.002575
0.001053
0.000919
0.000560
0.000526
0.000513
0.000500
0.000440
0.000333
0.000273
0.000267
0.000250
0.000250
0.000250
0.000200
0.0001720.000156
0.000143
0.000143

Number of
Being
Price
Used in Municipali
(YEN)
the
ties
Reference
Records
12,000
42
146
4,660
12
113
9,500
10
112
71,84566
134
25,000
14
78
3,800
2
73
7,800
4
144
6,000
3
112
25,00011
42
18,000
6
40
11,000
3
159
7,500
2
113
48,00012
128
20,0005
119
24,000
6
97
15,000
3
158
5,800
1
119
83,40013
133
28,000
4100
49,000
7
53

Ratio

69.2%
53.6%
53.1%
63.5%
37.0%
34.6%
68.2%
53.1%
19.9%
19.0%
75.4%
53.6%
60.7%
56.4%
46.0%
74.9%
56.4%
63.0%
47.4%
25.1%

6. Discussion
As shown in Table 2, the number of city libraries holding Encyclopedia of Modern Japanese
Literature (Nihon Kindai Bungaku Daijiten) is 43, which means seven (50 minus 43) city
libraries do not hold it. The NP of Encyclopedia of Modern Japanese Literature is 0.003500,
which is the highest among the 77 sample reference books (as shown in Table 4). Its price is12,000 yen and it is not very expensive. With these, we would like to recommend that seven city
libraries purchase it and add it to their reference collections. A similar thing can be said forEncyclopedia of Japanese People and prefectural libraries. Although its NP is the fourth highest(0.000919) among the 77 sample reference books, one prefecture (47 minus 46) does not hold it
as shown in Table 2.
Among inexpensive reference books, Encyclopedia of Westerners (4,660 yen) and Catalog
of Translated Literary Work in the Meiji, Taisho, and Showa Eras (3,800 yen) have high NPs(second and sixth highest as shown in Table 4). There are many city, town, and village libraries
that do not hold them. To improve reference services at low cost, we expect such libraries topurchase these reference books.

7. Conclusions
In this study, we have made lists of popular, useful, and cost-effective reference books based on
our investigations. The lists contain information about which types of municipality (such as cityor village) hold the reference books. We hope that these lists will be used by Japanese public
librarians to assess their reference collections and judge which reference books should bepurchased (added), considering the type of their library.
We have focused on reference books to improve reference services; however, reference
services are now being provided by using online reference tools. Databases and websites, aswell as printed reference books, are now popular and effective tools. Some libraries are
introducing databases instead of their printed versions. We have to investigate which databases
are being introduced in which libraries and compare their frequency of use and price with thoseof traditional reference books. Through these investigations, we believe that the current statusof reference tools in public libraries will be clarified and effective (or at least popular) tools willbe identified.
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