Eastern Japan Research Articles

New Depsides and Neuroactive Phenolic Glucosides from the Flower Buds of Rugosa Rose ( Rosa rugosa).

The flower buds of Rosa rugosa Thunb. have been commonly used as a source of rose oil and as an ingredient in tea in eastern Asia, including China, Japan, and Korea. Repeated chromatography of a hot water extract from the flower buds of R. rugosa led to the isolation and characterization of three new depside glucosides, rosarugosides A-C (1-3), along with three phenolic compounds, one ionone glucoside, four flavonoids, and two tannins having known chemical structures. Linarionoside A and 2-phenylethyl-(6- O-galloyl)-β-d-glucopyranoside were isolated from R. rugosa for the first time in this study. The structures of the new compounds 1-3 were elucidated by interpreting one- and two-dimensional nuclear magnetic resonance spectroscopic and mass spectrometric data. Among the isolates, a new depside glucoside (1) and two major phenolic glucosides (4 and 5) improved MK-801-induced sensorimotor gating deficits, which were measured via an acoustic startle response test in mice.

High-resolution wave climate hindcast around Japan and its spectral representation

A 34-year high-resolution ocean surface wave climate hindcast around Japan is presented, and the wave climate around Japan is examined from a spectral point of view. The spectral wave model is forced by the sea surface wind data obtained from the JRA-55 atmospheric reanalysis. The wave climate hindcast is validated by comparing it with buoy observations around Japan. The correlation coefficient of the significant wave height is 0.9. The correlation coefficient of the mean wave period is 0.8 for the Japan Sea and Pacific side of eastern Japan and 0.7–0.8 for the Pacific side of western Japan. The wave climate is represented by temporal-mean two-dimensional wave spectra. The characteristics of the spectral wave climate are investigated by classifying them into three types. Distinctive characteristics of the mean wave spectra along the Japan Sea are narrower band widths for both the period and direction. The mean wave spectra along the Pacific side of eastern Japan are characterized by swells with a spectral peak propagating from the northeast. The distinctive spectral features corresponding to the Pacific side of western Japan are bi-modal peaks with long-period components typically generated by typhoons. The variability in the monthly mean wave spectra is examined using an empirical orthogonal function (EOF) analysis. In the winter, it is found that the wave height variability (EOF 1st mode) is related to wave direction variability (EOF 2nd mode) at locations 1000 km apart via the sea level pressure variance over the North Pacific. In the summer, the EOF 1st mode corresponding to the Pacific side locations is dominated by the variability in typhoon-generated swells. The spectral wave climate representation provides new insight into the wave climate around Japan with clear relationships between the atmospheric conditions, the wave height, direction, and period.

Of Silk and Synecdoche: Economic Histories of Yokohama across Historical Scales - Yokohama and the Silk Trade: How Eastern Japan Became the Primary Economic Region of Japan, 1843–1893. By Yasuhiro Makimura. Lanham, Md.: Lexington Books, 2017. xx, 255 pp. - The Merchant's Tale: Yokohama and the Transformation of Japan. By Simon Partner. New York: Columbia University Press, 2018. xxii, 291

Of Silk and Synecdoche: Economic Histories of Yokohama across Historical Scales - Yokohama and the Silk Trade: How Eastern Japan Became the Primary Economic Region of Japan, 1843–1893. By Yasuhiro Makimura. Lanham, Md.: Lexington Books, 2017. xx, 255 pp. - The Merchant's Tale: Yokohama and the Transformation of Japan. By Simon Partner. New York: Columbia University Press, 2018. xxii, 291

Abundance decline in the narrow‐ridged finless porpoise population off the Pacific coast of eastern Japan

AbstractThe narrow‐ridged finless porpoise Neophocaena asiaeorientalis is a small‐toothed whale with a coastal habitat and is sensitive to human activity. Aerial sighting surveys were conducted in 2012 to evaluate the abundance and distribution of the Sendai Bay‐Tokyo Bay population off the Pacific coast of eastern Japan. We flew along 35 east–west transects at intervals of 11.6 km over the study area between 34°57′ and 38°21’ N. In total, 25 groups were detected by two observers. The mean group size was 1.44 individuals. Porpoise abundance was estimated to be 1,491 individuals (coefficient of variation = 32.4%), which was lower than the abundance estimated in 2000 (z test, p < 0.05). A population decline trend during 2000–2012 was also detected using four available abundance estimates (Bootstrapping linear regression, p = 0.040). A possible cause of this decline was coastal habitat disturbance and deaths by tsunami waves caused by the 2011 Great East Japan Earthquake. Density was as low as 0.221 individuals/km2, which is among the lowest levels in Japanese waters. Furthermore, distributional gaps reconfirmed by the present study and past genetic studies show that the population should be divided into at least two populations: northern (“Sendai Bay‐Fukushima”) and southern. Density decline was detected in the northern population between 2000 and 2012. Unlike the earthquake, human activities may continue to affect the porpoises. Viability analyses of these small populations should be conducted in the future.

A 30-year record reveals re-equilibration rates of 137Cs in marine biota after the Fukushima Dai-ichi nuclear power plant accident: Concentration ratios in pre- and post-event conditions

Concentration ratios (CRs), expressed by dividing 137Cs activity in seawater by that in marine biota (mainly fish), were obtained from the monitoring of 137Cs in coastal areas around Japan between 1984 and 2016. Before the TEPCO Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident (1984–2010), mean CRs of 137Cs, mainly from global fallout (i.e. CRGF), were almost constant for each species throughout the monitoring period, but were different among species, while the values for several species were dependent on their length (i.e. CRGF-SIZE). Thus, CRGF and CRGF-SIZE values for 29 of marketable species are given here as references for conditions where marine biota are in approximate equilibrium (or steady state) with their host water with respect to 137Cs activities in the marine environment. After the FDNPP accident (2011–2016), the impact of the accident has been sustained in eastern Japan waters as indicated by apparent CRs (CRas) which are being used here as indicators of disequilibrium between organisms and their host water. The recession rates of this disequilibrium (the effective CRa half-lives) ranged from 100 to 1100 days. The identified distinct variation was due to the sample locations, even for the same species, because of the change in 137Cs activity concentrations in their host water and diet preference differences. Variation among species, even those captured from the same area, was mainly due to diet differences as well as metabolic-physiological differences in 137Cs retention. Thus, our results from >30 years of systematically monitoring have helped quantify the recession rates of post-FDNPP disequilibrium of 137Cs in biota for assessment of how long term is required from contaminated condition by underlying spatial, inter- and intra-species factors.

The State and Cause of Psychological Changes Seven Years after the Great East Japan Earthquake

The aim of this study is to determine the psychological state and the cause of any changes in the psychological state of survivors of the Great East Japan Earthquake (GEJE) seven years after the event. The GEJE was a catastrophic disaster that struck a wide area eastern Japan. As a result, victims needed to live in shelters or temporary housings for a prolonged period. Consequently, many elderly who had been affected lost hope or had difficulty reconstructing their lives, with many eventually choosing to commit suicide or to die alone. These effects reveal a complicated process of psychological recovery and chronic distress. This study, therefore, provides a longitudinal examination of the psychological state of GEJE victims over the course of 7 years, both individually and collectively. We sampled 10 victims of the GEJE, asking them to draw a line describing the transition of their psychological state and then to describe specific episodes in which they were aware of changing in their psychological state. We subsequently found four patterns of psychological transition among victims in this study. Moreover, we found that victims’ psychological state was prone to change when triggered by circumstance in living, health status, and their relationship with their community.

Study of Soil Erosion for Evaluation of Long-term Behavior of Radionuclides Deposited on Land

The accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) resulted in the deposition of large quantities of radionuclides over parts of eastern Japan. Radioactive contaminants have been observed over a large area including forests, cities, rivers and lakes. Due to the strong adsorption of radioactive cesium by soil particles, radioactive cesium migrates with the eroded soil, follows the surface flow paths, and is delivered downstream of population-rich regions and eventually to coastal areas. In this study, we developed a model to simulate the transport of contaminated sediment in a watershed hydrological system and this model was compared with observation data from eroded soil observation instruments located at the Korea Atomic Energy Research Institute. Two methods were applied to analyze the soil particle size distribution of the collected soil samples, including standardized sieve analysis and image analysis methods. Numerical models were developed to simulate the movement of soil along with actual rainfall considering initial saturation, rainfall infiltration, multilayer and rain splash. In the 2019 study, a numerical model will be used to add rainfall shield effect by trees, evaporation effect and shield effects of surface water. An eroded soil observation instrument has been installed near the Wolsong nuclear power plant since 2018 and observation data are being continuously collected. Based on these observations data, we will develop the numerical model to analyze long-term behavior of radionuclides on land as they move from land to rivers, lakes and coastal areas.

Vertical Structures of Dust Aerosols over East Asia Based on CALIPSO Retrievals

The spatiotemporal and especially the vertical distributions of dust aerosols play crucial roles in the climatic effect of dust aerosol. In the present study, the spatial-temporal distribution of dust aerosols over East Asia was investigated using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) retrievals (01/2007–12/2011) from the perspective of the frequency of dust occurrence (FDO), dust top layer height (TH) and profile of aerosol subtypes. The results showed that a typical dust belt was generated from the dust source regions (the Taklimakan and Gobi Deserts), in the latitude range of 25°N~45°N and reaching eastern China, Japan and Korea and, eventually, the Pacific Ocean. High dust frequencies were found over the dust source regions, with a seasonal sequence from high to low as follows: spring, summer, autumn and winter. Vertically, FDOs peaked at about 2 km over the dust source regions. In contrast, FDOs decreased with altitude over the downwind regions. On the dust belt from dust source regions to downwind regions, the dust top height (TH) was getting higher and higher. The dust TH varied in the range of 1.9–3.1 km above surface elevation (a.s.e.), with high values over the dust source regions and low values in the downwind areas, and a seasonally descending sequence of summer, spring, autumn and winter in accord with the seasonal variation of the boundary layer height. The annual AOD (Aerosol Optical Depth) was generally characterized by two high and two low AOD centers over East Asia. The percent contribution of the Dust Aerosol Optical Depth to the total AOD showed a seasonal variation from high to low as follows: spring, winter, autumn and summer. The vertical profile of the extinction coefficient revealed the predominance of pure dust particles in the dust source regions and a mixture of dust particles and pollutants in the downwind regions. The dust extinction coefficients over the Taklimakan Desert had a seasonal pattern from high to low as follows: spring, winter, summer and autumn. The results of the present study offered an understanding of the horizontal and vertical structures of dust aerosols over East Asia and can be used to evaluate the performance aerosol transport models.

Future Changes in Monthly Extreme Precipitation in Japan Using Large-Ensemble Regional Climate Simulations

AbstractThis study investigated future changes in monthly extreme precipitation in Japan during summer (June–August). The uncertainties in estimating extreme monthly precipitation were analyzed using large-ensemble regional climate simulations for both present and 4-K warmer climates. The main diagnostics were based on the 100-yr return values of monthly total precipitation PT100 estimated from a best-fit probability distribution. Under the warmer climate, PT100 was projected to increase in approximately 87%, 88%, and 78% of the total number of stations for June, July, and August, respectively, suggesting that once-per-century monthly precipitation will increase as temperature increases over a wide area of Japan, although large regional variations will exist. The western part of Kyushu and the Hokkaido region showed significant and moderately robust increases in PT100 throughout the summer months. In contrast, a considerable and robust increase was projected only in June in the Nansei Islands. The percentage change in PT100 was small in western and eastern Japan, and thus the sign of the change was uncertain. Further analysis indicated that uncertainty in internal variability is more important than uncertainty in the SST scenario for future projections of monthly precipitation extremes.

Importance Analysis of Decision Making Factors for Selecting International Freight Transportation Mode

Currently, the competition among carriers in the international freight service industry is getting fierce. In particular, the LCC (Low Cost Carriers) in Korea secured the licenses for international freight delivery service. However, due to the high costs, most shippers prefer car ferry services over air transportation, even though the service level of air transportation is considerably better. The present paper investigates how the LCCs, as compared to car ferry services, secure the competitive advantage in the international transportation service as compared to car ferry services. We have focused on the factors shippers regard as the most important for selecting transportation mode. For a reasonable comparison, we have limited the business area to the north eastern Asian countries, including Korea, China, Japan, and Russia. We have developed a questionnaire for the shippers who export their own product in these countries from Korea. Based on the results of fuzzy-AHP, it can be concluded that the factors related to the reliability and convenience are regarded as the important factors for selecting the transportation mode. Furthermore, the results of this study can be used by LCCs to develop their own strategies for competing with car ferry services.

Comparison of predation risks for small fishes in salt marsh microhabitats in Lake Hinuma, eastern Japan, using tethering experiments

To clarify the role of salt marsh creeks as fish refuges, predation risks for two small species (the nektonic Oryzias latipes and benthic Acanthogobius lactipes) were compared among three microhabitats (upper and lower areas of a creek, and marsh edge separate from the creek) in a salt marsh in Lake Hinuma, eastern Japan, in July 2016, using daytime tethering experiments. The survival rate of O. latipes was highest in the upper creek (96%) and lowest at the marsh edge (62%), whereas no significant differences were found among the microhabitats for A. lactipes, with high survival rates (> 90%) in all microhabitats. Individual numbers of larger piscivorous fishes, determined by fyke net sampling, were greatest at the marsh edge, whereas no individuals were recorded in the upper creek, which was characterized by shallower depths and lower dissolved oxygen levels. The results suggested that the upper creek provides potential refugia for O. latipes, which occupied the upper and middle layers of the water column and exhibited hypoxia tolerance. The higher survival rate of benthic A. lactipes at the marsh edge may be due to their cryptic coloration in relation to bottom sediments, which helps them to avoid predation.

Long-Term Evolution of the Deviatoric Background Stress in the Focal Region of the 2011 Tohoku-Oki Earthquake

On 11 March 2011, a giant interplate earthquake of magnitude Mw 9.1 struck Tohoku-Oki area in eastern Japan. The earthquake is acknowledged to have permanently altered the stress field in and around the focal region. To capture the temporal change of the overall stress field, I examined 1251 focal mechanisms, from the NIED MT catalog, that occurred before and after the Tohoku-Oki earthquake from January, 2006 to January, 2017 in the focal region near the subducting slab. The examined observations were grouped into six periods, and based on the selected NIED MT catalog, the stress regime in each period was obtained by using the damped stress tensor inversion method. Based on the temporal evolution of stress rotation, the corresponding deviatoric stress level was estimated using a simplified 2D model. Results of the 10-year seismic stress cycle show that several years before the Tohoku-Oki earthquake, the stress accumulation level seems to have experienced an acceleration process. Studies suggest that this increasingly critically stress state combined with the sufficiently reduced coupling rate off the Tohoku area finally resulted in the unprecedented megathrust event. The coseismic process was violent and released almost all of the deviatoric stress that presented before the main shock. The resultant stress state even reached frictional overshoot. Thus, the postseismic stress pattern in the source region was reshaped significantly, especially for the upper plate and updip portion of the lower plate. After the main shock near the rupture surface, a surprisingly rapid and high-level stress reloading occurred within several postseismic years. To reconcile the classical subduction zone earthquake generation cycle model, the event may be described as an instantaneously decoupled stress state between the upper and inner plates.

Abnormal Gravity Wave Activity in the Stratosphere Prior to the 2016 Kumamoto Earthquakes

AbstractEarthquake (EQ) prediction is an essential topic in recent geophysics and disaster management. In order to explain EQ precursory phenomena, especially the ionospheric perturbations, a few hypotheses have been proposed as the mechanism of lithosphere‐atmosphere‐ionosphere coupling. The most reliable seems to be the atmospheric gravity wave (AGW) hypothesis, because a lot of subionospheric very low frequency (VLF) observations and also ground surface measurements support this hypothesis. However, no direct signature of AGW activity in the middle atmosphere has been yet obtained. So in this study, we have used the ERA5 reanalysis data to investigate the tempo‐spatial evolution of stratospheric AGW activity before a recent huge seismic event of the 2016 Kumamoto EQ on 15 April (Mw7.2). It was found that the AGW potential energy is enhanced significantly during about 1 week before the EQ. The enhancement was mainly distributed around the EQ epicenter and expanded toward eastern Japan. The AGW activity was highest around 11 April, then it calmed down and returned to the background level right before the EQ. These results were compared with the subionospheric VLF observations during the same period, and then the tempo‐spatial evolutions of the lower ionospheric perturbation are found to be very consistent with the stratospheric behavior. The present paper reports on the first finding that the abnormal AGW activity in the stratosphere is detected before a major EQ, and the coincidence of stratospheric AGW activity with VLF subionospheric perturbations provides further support to the AGW hypothesis of the lithosphere‐atmosphere‐ionosphere coupling process.

A phylogenetic study of Chinese Polygonatum (Polygonateae, Asparagaceae)

Polygonatum Mill., which consists of more than 60 species are mainly distributed in eastern Asia, especially China and Japan, has received considerable attention from plant taxonomists. Nevertheless, there are still gaps in our knowledge of this genus, especially concerning those species that are endemic to China and which have often not been included in previous studies. Here, we re‐evaluate the taxonomy of 28 Chinese Polygonatum species with emphasis on molecular evidence. Phylogenetic analyses were carried out on sequence data from four plastid DNA regions: atpB‐rbcL, matK, rbcL and rps16, using maximum parsimony and Bayesian approaches. Analyses of the combined datasets of the four regions revealed that: 1) Chinese Polygonatum are monophyletic at the current level of sampling; 2) three major lineages in Polygonatum are well supported and largely correlated with cytological and morphological characters; 3) our results, along with the results of previous works support that P. simizui is a synonym of P. odoratum, and 4) Polygonatum cirrhifoliodes is shown to be distinct from P. cirrhifolium.

Assessing the role of social media in tourism recovery in tsunami-hit coastal areas in Tohoku, Japan

Social media have become increasingly popular. However, there has been little investigation on how to effectively mobilize this newly emerging tool to promote tourism in rural areas. The aims of this article are twofold. First, among social media, we explore the role of Twitter for tourism promotion, especially by focusing on the recovery process of tourism in a rural area affected by the huge earthquake and tsunami, Magnitude 9.0, which hit eastern Japan in March 2011. Second, to approach the first purpose, we compare two types of tourism: ordinary tourism and ‘volunteer tourism’. As to the latter, a massive number of volunteers came to these areas to help in the recovery work from the devastation such as removing debris and helping evacuees rehabilitate their lives in Iwate prefecture. We employed a text-mining method to find keywords used in the official Twitter account issued by the Iwate Prefectural government and time-series regression models to identify factors that promote the two types of tourism. Data were collected using official statistics on incoming numbers of ordinary tourists and volunteer tourists. Tweeted information was provided by Iwate Prefecture. The results revealed that, first, tweeted information on cultural and natural heritage had a positive relationship with the number of incoming tourists while information on disaster-related words had negative effects. In contrast, second, tweeted information on tourism resources worked negatively toward the number of volunteer tourists while that on rehabilitation/reconstruction and on volunteers worked positively. Consequently, it is important to design support measures that enable the local tourism sector to attract incoming tourists after a drop-in volunteer tourism as reconstruction of the disaster area progresses. In this context, our results suggest how to effectively utilize Twitter for this purpose.

Anammox and Denitrification in the Intertidal Sediment of the Hypereutrophic Yatsu Tidal Flat, Japan

An increase in available nitrogen loading in intertidal ecosystems causes eutrophication and macroalgae blooms. Denitrification and anaerobic ammonium oxidation (anammox) lead to the removal of bioavailable nitrogen, but few studies have examined this in intertidal sediments. The sediment anammox and denitrification rates in September 2015 and November 2016 were measured using a 15N tracer technique at two sites, with and without macroalgae, in the hypereutrophic Yatsu tidal flat, eastern Japan. At both sites, the rate of N2 production via anammox was consistently low compared with that via denitrification, accounting for < 7% of the total N2 production. In a fed-batch incubation experiment, the anammox rate increased in the surface sediment after 3 months. However, the contribution of anammox to nitrogen removal did not exceed that of denitrification, suggesting that denitrification is the major pathway for conversion of inorganic nitrogen to N2, and that anammox plays a limited role in nitrogen removal in the Yatsu tidal flat. Denitrification activity measured from August 2012 to January 2017 using the acetylene block method was higher in the sediment with macroalgae than that without. Multiple linear regression analysis revealed that denitrification in the sediment with macroalgae was limited by the nitrogen substrate, likely due to competition with macroalgae for nitrogen. Temperature and H2S production under macroalgae cover might also affect denitrification. In comparison, the organic carbon content was a key factor regulating heterotrophic denitrification in the sediment without macroalgae. These findings suggest that the occurrence of macroalgae changes the progress of denitrification in intertidal ecosystems.

Phylogeography of lethal male fighting in a social spider mite.

When males fight for access to females, such conflict rarely escalates into lethal fight because the risks and costs involved, that is, severe injury or death, are too high. The social spider mite, Stigmaeopsis miscanthi, does exhibit lethal male fights, and this male–male aggressiveness varies among populations. To understand the evolution of lethal fighting, we investigated aggressiveness in 42 populations and phylogenetic relationships in 47 populations along the Japanese archipelago. By analysis of the male weapon morph, a proxy for aggressiveness, we confirmed the existence of a mildly aggressive (ML) form, besides the low aggression (LW) and high aggression (HG) forms reported earlier. To evaluate demographic history of these three forms, we employed the approximate Bayesian computation approach using mtCOI sequences and taking into consideration the postlast glacial expansion history of the host plant, Miscanthus sinensis. As results, hierarchical split models are more likely to explain the observed genetic pattern than admixture models, and the ML form in the subtropical region was considered the ancestral group. The inferred demographic history was consistent with the one reconstructed for the host plant in a previous study. The LW form was split from the ML form during the last glacial period (20,000–40,000 years BP), and subsequently, the HG form was split from the ML form at the end of or after the last glacial period (5,494–10,988 years BP). The results also suggest that the mite invaded Japan more than once, resulting in the present parapatric distribution of LW and HG forms in eastern Japan.

Molecular phylogeny and diversification timing of the Nemouridae family (Insecta, Plecoptera) in the Japanese Archipelago.

The generation of the high species diversity of insects in Japan was profoundly influenced by the formation of the Japanese Archipelago. We explored the species diversification and biogeographical history of the Nemouridae Billberg, 1820 family in the Japanese Archipelago using mitochondrial DNA and nuclear DNA markers. We collected 49 species among four genera: Indonemoura Baumann, 1975; Protonemura Kempny, 1898; Amphinemura, Ris 1902 and Nemoura Latreille, 1796 in Japan, China, South Korea and North America. We estimated their divergence times—based on three molecular clock node calibrations—using Bayesian phylogeography approaches. Our results suggested that Japanese Archipelago formation events resulted in diversification events in the middle of the Cretaceous (<120 Ma), speciation in the Paleogene (<50 Ma) and intra-species diversification segregated into eastern and western Japan of the Fossa Magna region at late Neogene (20 Ma). The Indonemoura samples were genetically separated into two clades—that of Mainland China and that of Japan. The Japanese clade clustered with the Nemouridae species from North America, suggesting the possibility of a colonisation event prior to the formation of the Japanese Archipelago. We believe that our results enhanced the understanding both of the origin of the species and of local species distribution in the Japanese Archipelago.

Frontolysis by surface heat flux in the eastern Japan Sea: importance of mixed layer depth

Frontolysis mechanisms by which surface heat flux relaxes the sea surface temperature (SST) front in the eastern Japan Sea (JS) are investigated in detail using observational datasets. On the warm southern side of the front, larger air–sea specific humidity and temperature differences induce stronger turbulent heat release compared to the cool northern side. As a result, stronger wintertime cooling and weaker summertime warming occur south of the front, and the meridional gradient in the surface net heat flux (NHF) tends to relax the SST front throughout the year. In the mixed-layer deepening phase (September–January), a higher entrainment velocity occurs on the warm southern side because of weaker stratification. Since the resulting thicker mixed layer on the southern side is less sensitive to surface cooling, the mixed layer depth (MLD) gradient damps the frontolysis by the NHF gradient. In the shoaling phase (April–June), a deeper mixed layer south of the front is caused by the weaker warming and reduced sensitivity of the thicker mixed layer to a shoaling effect by shortwave radiation. Owing to weaker sensitivity of the thicker mixed layer on the southern side to surface warming, the MLD gradient enhances the frontolysis by the NHF gradient. Therefore, it is shown that the mixed layer processes cause seasonality of weaker (stronger) frontolysis by surface heat fluxes, damping (enhancing) the frontolysis by the NHF gradient in winter (summer). This study reveals unique features of the frontolysis in the eastern JS compared with the Agulhas Return Current and Kuroshio Extension regions.

Yokohama and the Silk Trade: How Eastern Japan Became the Primary Economic Region of Japan, 1843–1893 by Yasuhiro Makimura

Yokohama and the Silk Trade: How Eastern Japan Became the Primary Economic Region of Japan, 1843–1893 by Yasuhiro Makimura