２０２２年度

公立大学法人北九州市立大学特別研究推進費

実績報告書
2023 年 4 月 15 日

北九州市立大学長 様（所属・職名）外国語学部・講師（氏名）Eum Wonsub（オム ウォンソブ）公立大学法人北九州市立大学特別研究推進費に係る研究実績について、次の通り報告します。
研究課題名

交付決定額
執行額
執行残額

日本の地域産業多角化: 輸出構造の経路依存的進化から
Regional Industrial Diversification in Japan: From Pathdependent Evolution of Export Structures合計
使用内訳（単位：円）
599,700
備品費
消耗品費
報酬
その他
旅費交通費
596,0160
162,844360,630
72,542
0
3,684
所属・職名
外国語学部・講師

氏名
Eum Wonsub

役割分担等
研究代表者

共同研究者

研究分野：地域経済学、進化経済学
キーワード：地域、多角化、輸出構造、経路依存性
研究成果の概要（和文）本研究の主な目標は、輸出構造を研究することにより、日本の地域産業構造の進化を明らかにし、各地域の効果
的かつ効率的な産業発展の方向性を提供することである。本研究では、1988 年から 2020 年にかけて各都道府県に所在する税関から地域輸出データベースを構築し、産業構造の変化を推計した。本研究の分析結果は韓国学会（2022 Korea Technology Innovation Society Spring Conference）と国際学会（Asia PacificInnovation Conference 2022）で発表された。本研究の学問的成果は、1）輸出異質性や産業構造変化の経路依存性を地域レベルで分析すること、2）日本地域におけるデータの解析により、アジアからの実証的証拠を提供すること、である。
研究成果の学術的意義や社会的意義
Only a few studies until now have attempted to analyze the Japanese regional export structuresfrom the evolutionary economic perspective of path-dependence and economic complexity. By
linking the two keywords of complexity in export structure and path-dependent diversification,
this research enriches the current discussion of evolutionary economic geography by providing
empirical evidence on the dynamics of export structures. Also, this study has strong implications
on both Japanese industrial policies and SDGs. Japanese government has been investing much
effort on regional revitalization. This study provides a direction for what industry each prefecture
should be targeting at by looking at the past patterns of structural changes and current export
structures. In addition, this study is closely linked with job opportunities and economic growth(SDG 8) and industry and innovation (SDG 9). Sustainable economic/industrial growth and job
creation in regions are key interests of both developed and developing economies. This study
suggests an effective way to set target industries for sustainable regional development, by
studying the past and present of Japanese prefectural export structures.

1. 研究の背景
Recently, Japanese government has been focusing on re-vitalizing the local economies (地方創生), and local economies in Japan have been experiencing a continuous decrease in population,
and aging societies. As a result, local economies are experiencing stagnated growth over few
decades, and local governments are supporting local industries with policy measures with
substantial budget. However, there was a limited success in developing new industries orindustrial upgrading in terms of economic complexity. It is hard to tell which comes first between
decrease in population or slowing economic growth and job creation, but it is certain that “whatto do” for the Japanese local economies is a key issue for revitalization. Therefore, it isnecessary to understand the differences and dynamic changes of regional industrial structuresof Japanese regions, so that it is clearer to see which industries are promising for efficient andeffective diversification of each prefecture.
2. 研究の目的
By analyzing the patterns of export structural changes, this research aims to provide answersof what industries Japanese regions should focus on, for eventual efficient and effective
regional revitalization.
• H1-1) Japanese regions show heterogeneous export structures.
•H1-2) Japanese regions show heterogeneous export concentration.
•H2-1) Japanese regions showed divergence in export structures over time.
•H2-2) Japanese regions showed path-dependent development of export structure overtime.
3. 研究の方法
In order to answer these questions, this study constructs a regional export database based on
125 customs (税関) across prefectures from 1988 to 2020 to estimate industrial structurechanges. It uses both statistical and econometric methodologies to test the heterogeneity ofregional industrial structures, and their evolution patterns over years.
4. 研究成果The results confirm that there is a heterogeneity among the Japanese regional export structures,
and a strong path-dependence during the regional export diversification. These results suggestthat it is important to recognize the regional differences in Japan, and a uniform policy may not
be effective in supporting regional exports. Also, the results show that regions are more likely to
use the current capabilities, and diversify into nearby products.
This study has been presented in a Korean domestic conference (2022 Korea Technology
Innovation Society Spring Conference), and an international conference (Asia Pacific Innovation
Conference 2022) with the results from the Kyushu area.

Path-dependent Evolution of Regional Export
Structures in Japan
Wonsub Eum,1 Sira Maliphol,2,a Taewon Kang3

Dept. of English, The University of Kitakyushu, Kitakyushu, Japan
Dept. of Technology and Society, SUNY-Korea, Songdo, South Korea
3
Graduate School of National Public Policy, Chungnam National University, Daejeon, South Korea
1

2

Abstract— The main purpose of this study is to elucidate theregional capability development of Japanese regions throughstudying export structures, in order to provide directions for
effective and efficient regional industrial development.
Specifically, this study studies whether and to what extent the past
Japanese regional export structure contributes to thediversification in the future in addition to the analysis of current
structural heterogeneity. In order to answer these questions, thisstudy constructs a regional export database based on 125 customs
across prefectures from 1988 to 2020 to estimate industrial
structure changes. This study provides statistical and econometric
evidence on the heterogeneity of Japanese regional export
structures, and their evolution patterns over years. The results
suggest that it is important to recognize the regional differences inJapan, and a uniform policy may not be effective in supporting
regional exports.

I. INTRODUCTION
After decades of stagnant economic growth, Japan has
revitalized national industrial policy as a means to spur
economic growth. The goal of regional revitalization has
spanned administrations and targets industrial policy that seeks
to expand into global markets, i.e., exports [1]. Yet, the national
policy does not specify what industrial sectors each prefecture
should target or if they should even vary between regions.
Regional characteristics, however, vary. Although Japan’s aging
society is well-known, the change in demographics has different
effects in various regions around the country. Furthermore,resources vary between regions [2]. Therefore, the aim of thisstudy is to understand implications for Japanese regions byanalyzing the past and present of regional (prefectural) export
structures of Japan.
Export variety is important in economic performance andexport growth [3-4]. Most studies on export variety focuses on
firm- or country-level export variety, and suggested
heterogeneity among exporting firms [5-6] or heterogeneity
among countries [7-8]. In these models, the ex-post efficiency
of firms and capability of countries represented by export basket
determine the economic status of firms/countries [9]. Yet,differences in regional resources and capabilities also affecteconomic performance at the regional level [10]. Thus, there isa need to analyze the regional-level diversification andspecialization patterns, as regional division may also capture apart of this heterogeneity, if efficient firms are not evenly
distributed across regions.

This work was partially supported by the National Research Foundationof Korea under grant no. 2022R1G1A1006464.

Regarding the dynamics of export variety, recent studies
from economic geography argue that regions develop pathdependently. They argue that new industries which emerge in an
economy can benefit from existing, related industries, by
sharing inputs [8], and studies the spatial externalities andregional growth [11-12, 13]. Looking at the regional
developments of export structures is important from theperspectives of region-specific localized capability [14], as thedevelopment of capabilities occur through mechanisms thathave a strong regional bias [11]. Also, regions more easily
absorb knowledge when it is similar to the existing knowledge[15], for example, industry clusters benefitting fromtechnological complementarities [16-17].
Previous path-dependence studies are at firm-level orcountry-level [5,6, 18-20], and a few regional path-dependence
studies are limited to cases from Europe and the US [11,14].
This study fills these two gaps by 1) analyzing the export
heterogeneity among within a country at regional-level, and 2)
providing an empirical evidence of regional capability
development from Asia, with data from Japanese regions. This
study aims to analyze the past and present of regional export
structures of Japan, in order to give practical industrial policy
implications to Japanese regions. Specifically, this research tests
whether Japanese regions show heterogeneous export structuresand concentrations, and divergence and path-dependent
evolution of export structures over time. Specifically, this study
will ask the following questions.
H1: Japanese regions show heterogeneousconcentration (HHI) lead to increased exports.

exportH2: Japanese regions show path-dependent development ofexport structure over time.
If the prefectures’ export structures are different and havedifferent concentration (H1), and if the export structures
diverged as current export structures influenced the future
export structures (H2), then each prefecture should aim different
industries based on their current export structures andcapabilities. As a result, this study aims to suggest that rather
than one central-government-led revitalization policy, regional
policies based on regional export structures should take place.
In order to answer these questions, this study constructs aregional export database based on 125 customs acrossprefectures from 1988 to 2020 to estimate industrial structurechanges. It uses both statistical and econometric methodologies

to test the heterogeneity of regional industrial structures, andtheir evolution patterns over years. The results confirm that there
is a heterogeneity among the Japanese regional export structures,
and a strong path-dependence during the regional export
diversification. These results suggest that it is important torecognize the regional differences in Japan, and a uniform policy
may not be effective in supporting regional exports. Also, theresults show that regions are more likely to use the current
capabilities, and diversify into nearby products.
II. DATA & METHODOLOGY
A. DataThis study primarily depends on the yearly export data ofJapanese prefectures. This data is freely available at Trade
Statistics of Japan, in the forms of 1 year, 5 customs, and 10 HS2 digit dataset. This study covers 34 years, from 1988 through2021. There are 166 customs offices covering around 1200
industries. In other words, the dataset includes the export data𝑋𝑋𝑐𝑐,𝑖𝑖,𝑡𝑡 from each customs office, c; each industry, i; and eachyear, t. Fig. 1. shows an example of the data structure.
Customs
Office (c)Prefecture

Industry (i)Year (t)ExportVolume(𝑿𝑿𝒄𝒄,𝒊𝒊,𝒕𝒕 )NaritaTokyo

Automobile

1999

1,000,000

Narita

Tokyo

Rice

1999

500,000

HakataFukuoka

Automobile

2000

2,000,000

Moji

Fukuoka

Automobile

2001

3,000,000

Fig. 1. Sample of dataset and data structure.

Largely, Japanese customs offices are divided into 9 areas:
Tokyo, Yokohama, Kobe, Osaka, Nagoya, Hakodate, Moji,
Nagasaki, and Okinawa. The current dataset focuses on Kyushu
area that covers 3 (Moji, Nagasaki, Okinawa) out of these 9
areas, between 1988 and 2021. This includes 45 customs offices
out of 166 total, such as but not limited to Moji, Hakata,
Shimonoseki offices from Moji area, Nagasaki, Kumamoto,Kagoshima offices from Nagasaki area, and Okinawa andIshigaki offices from Okinawa area.
B. Methodology
Regarding the measurement of export concentration, thisstudy adopts commonly used Herfindahl-Hirschman Index(HHI), which is mathematically expressed as:
𝐻𝐻𝐻𝐻𝐻𝐻 = ∑𝑖𝑖 (𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸ℎ𝑎𝑎𝑎𝑎𝑎𝑎𝑖𝑖 )2(1)

Regarding the path-dependent development, this study
analyzes whether the past existence of comparative advantage
of a customs office influences the future comparative advantage
of it. To measure the comparative advantage, this study uses
Revealed Comparative Advantage (RCA) suggested by [21].
This measurement indicates comparative advantage of a country
in an industry at an year, by measures whether export share of aparticular product of a country is larger than that of the world.
This study uses export data at customs-office-level instead ofcountry-level, and RCA is calculated by comparing the office’s
share to the country’s share, instead of original comparison

between country’s share and the world’s share. Its mathematicalrepresentation is,
𝑅𝑅𝑅𝑅𝑅𝑅𝑐𝑐,𝑝𝑝 =𝑥𝑥(𝑐𝑐,𝑝𝑝)∑𝑝𝑝 𝑥𝑥(𝑐𝑐,𝑝𝑝)

�∑𝑐𝑐 𝑥𝑥(𝑐𝑐,𝑝𝑝)∑𝑐𝑐,𝑝𝑝 𝑥𝑥(𝑐𝑐,𝑝𝑝)(2)

where c stands for customs office, i stands for product (HS), andx for value of export volume.
Next, the concept of density is adopted from studies on
product space [11,14] to analyze the path-dependent
Development of industries. Density measurement is first basedon the proximity between products by calculating the probabilityof co-exporting, or in other words the minimum of the pairwise
conditional probability of customs office that export 𝑝𝑝1 and 𝑝𝑝2 .
The mathematical expression of proximity 𝜑𝜑𝑝𝑝1,𝑝𝑝2 between thetwo products is:
𝜑𝜑𝑝𝑝1,𝑝𝑝2 =min {P�RCA𝑥𝑥𝑝𝑝1 > 1�RCA𝑥𝑥𝑝𝑝2 > 1�,P�RCA𝑥𝑥𝑝𝑝2 > 1�RCA𝑥𝑥𝑝𝑝1 > 1�}(3)

By using the proximities between all products, density canshow the distance of a product from current export structure.
Density can also be simply stated as average proximity, because
it is the sum of proximities between a particular product andproducts with RCA, divided by the sum of all proximities linked
to that product. The mathematical expression of density 𝜔𝜔𝑝𝑝2
around product 𝑝𝑝2 is as follows:𝜔𝜔𝑝𝑝2 = � 𝑥𝑥𝑝𝑝1 𝜙𝜙𝑝𝑝1,𝑝𝑝2 �� 𝜙𝜙𝑝𝑝1,𝑝𝑝2
𝑝𝑝1

𝑝𝑝1

(4)

III. RESULTS

A. Stylized Facts
This section presents some stylized Facts on export
concentration of customs offices of Kyushu area. First, Fig. 2.
shows the export concentration of representative customs offices
from the three areas of Moji, Nagasaki, and Okinawa. There are
significant differences across these neighboring areas, as offices
from Moji (Hakata, Tobata, Itoshima, Moji) shows a lower
export concentration in general, whereas offices from the othertwo areas of Nagasaki (Miike, Sasebo, Nagasaki, Nagasaki
airport) and Okinawa (Okinawa, Ishigaki, Naha airport)
showed higher export concentration. These results indicate that
there is a need to distinguish the customs offices in Japan andanalyze the development of each custom, as there are notabledifferences across the customs offices.
Next, Fig. 3. shows the histogram showing the industry
densities across regions when there was a new industry at t+1(RCA<1 at t and RCA>1 at t+1) and no comparative advantage
emergence at t+1 (RCA<1 at t and RCA<1 at t+1). As productdensities vary across regions and entry into sectors vary acrossindustries, it can be expected that there would be differences in
the possibility of new industry emergence depending on the
product density. The result shows that products with new

comparative advantage at t+1 had higher product density at t. In
other words, having comparative advantage in related industries(higher density) at t leads to a higher possibility of acquiring
comparative advantage in the next period.

(a) MojiFig. 3. Industry densities across regions and entry into sectors acrossindustries

B. Regression Analysis
This section presents some preliminary results of regression
analyses on the relationship between export growth and export
concentration, and path-dependent industrial development. First,
Fig. 4. tests whether higher export concentration at year t leads
to higher export growth at year t+1. The results show that higher
export concentration, or higher HHI leads to lower export
growth in the future.
Baseline

Baseline

FE

FE

(1)

(2)

-2.722 ***-3.019***(0.805)(0.817)

Year dummy

No

Yes

Constant

2.778***

3.122***

Dependent variable
𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝑬𝒄𝒄,𝒕𝒕+𝟏𝟏
HHI_(c,t)(b) Nagasaki(0.373)(0.859)R-squared

0.18

0.111

Observations

1,308

1,308

Fig. 4. Regression results for export sector concentration

Next, Fig. 5. shows the results of the path-dependence
analysis, testing whether customs offices tend to havecomparative advantage in related export products to their current
export structures. The key independent variable is density
measure at t, and it shows positive and significant correlation
with RCA at t+1 across all models. Also, RCA at t is positively
and significantly correlated with RCA at t+1. This result showsthat not only the current comparative advantage, but also
comparative advantage in related industries influences the futureadvantage in exports.
(c) Okinawa
Fig. 2. Export concentrations of custom officesDependent

Baseline

Baseline

Baseline

Baselinevariable𝑹𝑹𝑹𝑹𝑹𝑹𝒄𝒄,𝒕𝒕+𝟏𝟏

OLS

ProbitOLS

Probit

(1)

(2)

(3)

(4)

0.693***

1.400***

0.644***

1.301***-0.002-0.016-0.003-0.017

Density_(c,t)

0.101***

0.800***

0.196***

1..097***-0.004-0.034-0.006-0.043

Year dummy

No

No

Yes

Yes

Country

No

No

Yes

Yes

0.130***-0.849***0.127***-0.771***-0.002-0.014-0.008-0.051

RCA_(c,t)

dummyConstant
R-squared

0.532

Log-likelihood
Observations

0.539-43290.6

116,485

116,485-42552.8
116,485

116,485

Fig. 5. Regression results for path-dependence

IV. DISCUSSION & CONCLUSION
This study examines factors of regional export performanceby constructing a novel dataset. The study considers different
industrial export structures as possible drivers of export growth.
The findings support the hypotheses that heterogeneous export
concentrations lead to increased export growth by sector (H1)and that export structures of Japanese regions are path dependent(H2). Regions in Japan show diverse structures of export
concentration, eventually leading to different export growth.
The implication of these findings is that economic
development policies at the national should consider
development of regional industrial structures for export rather
than the unified policy that is currently proposed. Since
industrial capabilities are largely defined by local capabilities
and resources, the variation across a country needs targeted
policies based on regional characteristics. Further, the granular
understanding of regional resources increase technologicalmanagement decisions based on strategic targets that are mostappropriate for each region.
It is important to recognize the regional differences in Japan,
and a uniform policy may not be effective in supporting regional
exports. Moreover, since path-dependence occurs as a part ofregional export diversification, regional resources capabilities
should build on existing resources and capabilities. Yet, when
diversifying new resources and capabilities, it is important todiversify into sectors, products, and technologies that are ‘near’
to existing sectors, products, and technologies.
The study has certain limitations that call for further research.
First, this study uses a limited dataset from certain prefectures inJapan. Data collection is currently ongoing. When the datacollection has been completed, an analysis of all the prefecture
data across Japan would provide improved results. Second, themodels employed can be improved by adding control variables.
Lastly, the results can be dissected to examine which sectors
each region has relative comparative advantage that define eachprefecture.

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