A city known for its soy sauce production, Choshi lies 100km east of Tokyo, in Chiba Prefecture. Soy sauce production began during Japan's Edo era, although it was widely used on sushi and tempura before then. But why Choshi? For Ground Detective Simon Wallis, the hints this time are "hard coastal rock" and "flatlands," which are said to be particularly suited to soy sauce production. But how could geology make such a difference? The Ground Detective is on the case!

Appearing at festivals and weddings, the red sea bream is an auspicious fish in Japan. A freshly caught sea bream isn't simply red; its scales also have a beautiful opalescent blue sheen. Anglers who wish to catch it must brave rough seas and fast currents as they maneuver shrimp at the end of their lines to lure the fish. Some seasoned veterans prefer to wind up their line by hand without a reel! Join master anglers in their divine duel with the object of their fascination: the red sea bream.

The Watari Museum of Contemporary Art, or the "Watari-um," is a privately-owned museum in Tokyo's central Shibuya Ward. In 1990, it was constructed from a design by architect Mario Botta in a uniquely triangular shape. Founder Watari Shizuko and her children Etsuko and Koichi held close dialogues with artists in order to present the most cutting-edge art. For a limited time in 2021, the museum will erect "art pavilions" all around Tokyo, as they seek out new perspectives in artistic beauty.

Deep in the countryside is the peaceful area of Maru-bashira in Iga in southern-central Japan. This tiny village of only about 650 people has long been known for a type of pottery called Iga ware. Even today, several potteries continue this craft. Fukumori Michiho is one of them carrying on the tradition. For over 400 years, her family's pottery has been firing its kilns. Michiho pours her heart and soul into making earthenware pots called "donabe." Her hope is that modern generations will come to appreciate this time-honored cookware. Creating her very own "donabe" recipes, she wants to see these traditional pots once again become a familiar sight in kitchens across Japan.

"It's kami (gods) that have helped us for generations." So says Sato Akihito (82), a 19th-generation Ai, or indigo, producer. Digging into a hot mound of Ai, he immediately knows what the Ai "wants." Ai makes an almost mystical color due to time, several fermentation processes and constant care. It requires a delicate balance between the power of humans and Ai, as well as dye artisans who are dedicated to the craft of Aizome, or indigo dyeing. We take a look at the incessant dialog between humans, fungus and plant matter, which epitomizes the Japanese attitude towards nature and beauty.

Yamamoto Yasuo (age 48), a 5th-generation soy sauce producer on Shodoshima Island in western Japan, started crafting wooden barrels himself. This was to preserve the traditional wooden barrel brewing method of soy sauce for the next generation. The body and flavor of soy sauce are imbued by microorganisms that inhabit the wooden barrels and breweries. However, due to industrialization, wooden barrel craftspeople have disappeared and usable wooden barrels could be lost in a few decades. Mr. Yamamoto started to reach out to fellow soy sauce brewers across Japan to encourage them to use his wooden barrels. "My job is not to make soy sauce. It is to connect our generation with the next. My ancestors have done the same." We'll take a close look at the Yamamoto and his unique way of having dual professions of crafting wooden barrels and brewing soy sauce.

The threat of COVID-19 infection is just around the corner. Anyone can be infected at any time. If someone was infected in the school, what should the students do? The students in Jiyu Gakuen, have begun to think about corona and discrimination for themselves.

Last December, the Hawaii state government decided to accept Japanese tourists, and flights to Hawaii were resumed. The airline industry in Japan was filled with hope for a bright future. However, in January 2021, the state of emergency was again declared in 11 prefectures, including Tokyo. As the spread of COVID-19 continued, the number of passengers at Haneda Airport decreased dramatically, and tenants of the airport's shopping areas have also kept their doors closed. But airport workers are perseveringly preparing to bring back air travel.

The fall 2020 campaign to boost domestic travel helped bring old and new hotels back to life. But late in the year, infection figures surged and Tokyo issued a second state of emergency. At one long-established hotel, a couple forced to postpone a large wedding once before faced having to do so again. A new hotel in Shibuya has taken measures such as reducing employee attendance to two-thirds, while finding a way to increase workspace by remodeling rooms and use the lobby as a gallery space.

At the foot of the Nikko mountains lives Yamamoto Yuichiro (age 70) and his son Jin-ichiro (45), who, without relying on any machines, produce the hardest natural ice in Japan. The season begins in late fall when they adjust the amount of spring water daily while waiting for cold weather. If the first centimeter freezes solid, then it will make fine ice. But if it doesn't, they will have to break it and start over. Yuichiro says, "Man can only do very little to nature. So the ice artisan's job is to just help the ice to grow without fighting nature." In December, they scrape snow to help the ice freeze and keep careful watch as it slowly grows until harvest time in 3 months. We take a close look at the efforts of these men who produce hard-to-melt ice in harmony with nature.

Summer in Japan is the season to catch a prized river dweller called Sweetfish, and the method to do so is quite unique. Instead of bait or a lure, anglers actually attach a Sweetfish to their line to hook the wild ones who try to chase the intruder out of their territory. This technique is called "fishing with a partner fish." Join us and watch the masters in action as they skillfully guide their scaly partners to hook the finest Sweetfish around!

Since ninja were engaged in espionage, they had to gather information and accurately convey it without anyone knowing. Typical means of information transmission included smoke signals, a cipher using knots in a rope, and special methods of transporting secret messages. But in the second half of the episode, we'll look at their ultimate method of concealing information: invisible ink! Find out how they did this, and follow Chris as he makes his own secret message with ninja techniques.

The Hojo clan was a warrior clan that ruled the Kanto region from the 15th to 16th century. Supporting their efforts to defeat enemies and maintain control was a mysterious group called the Fuma ninja. Their leader, Fuma Kotaro, is described in historical documents as a monster, and may have been the reason why they were so feared. We'll look at how the Fuma ninja took over castles and also guarded them for the Hojo clan.

The clear waters of the Akigawa River course through a verdant gorge, just 90 minutes west of Tokyo. They are home to a treasured fish that has been enjoyed for centuries -- the Ayu or Sweetfish. We meet 2 men who cherish this fish, in season briefly from early summer to early autumn. One has devoted his life to protecting its pure waters. The other saves its viscera to prepare a fermented delicacy. Their kitchens are full of gratitude for this life born and protected in the Akigawa River.

The Ground Detective is back! In this episode, he travels to Kagawa Prefecture on Shikoku Island. People come here from all around to enjoy its many udon noodle shops, numbering over 500. What is it about the local area that gives the udon noodles here their distinctive firm but sticky texture? Is it the fact that Kagawa faces an inland sea? Is it in the history of farming here? Is it related to earthquakes? The pieces of the puzzle are salt, flour and water, the only 3 ingredients for these noodles. And the Ground Detective is on the case!

Japan's world-famous lacquerware is prized for its versatility, beauty and shine, which is due to the varnish made from the sap of Urushi trees. This sap is harvested by hand in small amounts through a meticulous process of scraping and cutting. Tobita Yuzo (86) carries on a lifelong pledge of brotherhood to the Urushi trees as one of the last few remaining harvesters. To make sure this legacy continues, Tobita plants thousands of new trees in the hopes of making a forest full of Urushi.

We venture to the sandy coastline southwest of Tokyo where the water remains shallow far into the sea - perfect conditions for surf fishing enthusiasts. To catch a variety of tasty local fish, they pivot and swing their rod in a wide arc as they throw their line over distances that sometimes can exceed 200m! According to these anglers, casting their line as far as possible transports them to a fairytale wonderland where, along with their rig, they send their mind flying above the ocean.