How will tea production sites evolve with agricultural mechanization and robotics? The cutting edge of smart agriculture [Horiguchi Seicha / Daisuke Horiguchi]

Currently, more than 6 million tons of tea are produced worldwide. For the past 10 years this figure has been increasing by 100,000 tons each year. Of this amount, about 70,000 tons is produced in Japan. In other words, Japanese tea accounts for only 1% of the world’s tea production. Although only 1% of the world’s tea production, Japan has a unique tea culture, including the tea ceremony and sencha tea ceremony, and tea utensils such as kyusu and kettles for boiling water.

Inventions and innovations developed and improved only in Japan can also be found in tea production sites. One such example is a driven harvesting machine.

Over the past 100 years, tea harvesting in Japan has changed from handpicking, to hand shears, to portable harvesting machines, and then to driven harvesting machines. While hand-picking is still the dominant method of tea harvesting in the world, since the late 1980s, driven harvesting machines have become mainstream in Japan, and their harvesting efficiency is hundreds of times higher than that of hand-picking.

With smartphones now in each person’s hands, drones flying, and self-driving cars on the horizon, how will agricultural machinery evolve?

Horiguchi Seicha, located in Shibushi City, Kagoshima Prefecture, manages one of the largest tea farms in Japan, and has been working on mechanizing tea production sites for some time. In addition to the machines developed in-house, the company is collaborating with national research institutes and participating in research on unmanned harvesting machines, essentially harvesting robots.

This time, we spoke to Daisuke Horiguchi, the CEO of Horiguchi Seicha, who is at the forefront of tea and robotics.

Daisuke Horiguchi

Daisuke Horiguchi, is the representative director of Horiguchi Seicha and Wakohen. He was born in 1982 in Shibushi City, Kagoshima Prefecture. After graduating from university, he joined a tea producer in Shizuoka Prefecture, where he worked for four years. In April 2010 Horiguchi-san returned home to join Horiguchi Seicha/Wakouen, where his father was the president. In July 2018, he was appointed as the representative director of Horiguchi Seicha and Wakohen. Horiguchi-san is also a qualified Japanese tea instructor. The tea farm area is 300ha (of which 120ha they manage themselves).

What is Horiguchi Seicha, the frontrunner in the Japanese tea industry?

Q: What are the Horiguchi Seicha business activities?

Horiguchi: Our company consists of Horiguchi Seicha, which handles everything from raw leaf cultivation to refining process, and Wakohen, which sells processed tea wholesale and retail. Wakohen has 5 physical shops in Kagoshima Prefecture and an online shop.

In addition, there is the Saon no Kura – a restaurant with a creative tea menu, and the Osumi Sazen, a tea space based on the concept of a new tea culture proposed by the tea farmers.

We also have two concept brands: TEAET, which uses our own tea leaves, and Kakuhori, which specializes in single-origin tea.

You can clearly see how vast the tea fields and large factories are.

Horiguchi Seicha processes tea from 300 ha, of which 120 ha is managed by our company itself, and the remaining 180 ha is managed by 42 affiliated farmers.

There are two main types of affiliated farmers: those who are raw leaf farmers and bring their raw leaves to our Aracha factory, and those who manufacture their own tea at their own factory but also bring some of their raw leaves to our factory.

Due to the tough market conditions recently, some farmers have chosen to stop production at their own factories and bring all the fresh leaves they grow to us, while others have taken the hybrid option of continuing to operate their own factories and bringing some of their fresh leaves to us. Horiguchi Seicha does its best to meet the needs of all its affiliated farmers.

Affiliated farmers who support Shibushi together with Horiguchi Seicha.

Q: The Horiguchi Seicha Group not only produces tea, but also engages in tea retail and restaurant business, right?

Horiguchi: Yes, we are doing many things with the image of a winery-like place.

More than 30 years ago, in 1989, we simultaneously incorporated two companies: Horiguchi Seicha, a tea producer, and Wakohen, a tea retailer. At that time, I think it was quite unusual for a tea producer to also open a retail sales company.

However, as you know, the demand for tea leaves alone has been decreasing with the passage of time. Therefore, the Horiguchi Seicha Group came to believe that we needed to create a place to present tea to our customers.

Exterior view of the creative restaurant Saon no Kura

Menu available at creative restaurant Saon no Kura

So we decided to offer not only drinking tea, but also eating tea, and opened Saon no Kura, a creative tea restaurant, in 2016.

Saon no Kura is a restaurant in a renovated storage house, with a grand piano on the first floor and private rooms on the second floor, from which you can see the tea fields. You can enjoy a Japanese course meal using tea made by Horiguchi Seicha and ingredients produced in the Osumi Peninsula.

In addition, since Saon no Kura is located right in front of our tea factory, you can experience the tea steaming aroma from the tea factory during the tea season.

Osumi Sazen

In 2022, we opened Osumi Sazen under the concept of a new tea culture proposed by tea farmers. We created it with the desire to convey the value and enjoyment of tea that has existed since ancient times, while also incorporating new things in order to convey it to as many customers as possible.

Osumi Sazen

Horiguchi Seicha’s elite unit – the Tea Farm Force: Tea Rangers. The impetus for its creation was sustainable tea production.

Q: Please tell us about the theme of this time, the machines that work in the tea fields –  the Tea Farm Force: Tea Rangers.

The Tea Farm Force: Tea Rangers.

Horiguchi: At Horiguchi Seicha, we practice smart farming with integrated pest management (IPM).

IPM farming is a farming method that does not rely solely on pesticides, and the Tea Farm Force:  Tea Rangers is a central part of our IPM farming method.

The first machine developed was the Hurricane King. This is a machine that blows away pests not with pesticides, but with wind and water.

The Hurricane King, the first of the Tea Rangers.

The impetus for the development came from the experience of going to a tea field right after a typhoon and finding no pests. Thinking that we could blow away the pests with wind and water, we developed this product together with the manufacturer.

Black Shadow helps with difficult tasks that would take a lot of time to do by hand.

Black Shadow was also born from the idea that it would be great to mechanize the process of shading the tea fields, which was extremely hard work on rainy days.

Based on the idea that it would be great if a machine could do something in daily farm work, we created a total of five machines, including the Cyclone (developed by Kagoshima Prefecture), Steam Buster.SL, and Blanchette. We named them the Tea Field Force: Tea Rangers and even painted the machines different colors (laughs).

However, we are not currently using the Steam Buster.

Q: I heard that Horiguchi Seicha is working on a project to develop unmanned harvesting machines, but when did this start?

Horiguchi: In 2019, we were approached by Kagoshima Prefecture and a national research institute to work together on a demonstration project for unmanned harvesting machines. We felt that it would be meaningful to do this project in this production area, and that is when we decided to join it.

Q: Currently how many unmanned harvesting machines are used in tea fields?

We have tested two unmanned harvesting machines operated by one person in one large tea field.

People watching the unmanned harvesting machine.

At this stage the demonstration that we were supporting was a success.

Q: Does this mean that it is still a long way until we can operate unmanned harvesting machines on-site?

Horiguchi: There were times when we ran the machines, but there are restrictions on using automated machines, and sometimes it takes a lot more work to run them than expected, so we have to balance these factors when deciding whether to run them or not.

Specifically, when using automated, unmanned harvesting machines, the applicable safety level varies depending on the conditions under which they are used, and they must be operated within those constraints.

Another thing is that the unmanned harvesting machines have to be transported to the tea fields by trucks driven by people, and the harvested tea leaves have to be brought back by trucks also driven by people. 

We are considering whether or not to operate them, taking all of these factors into account.


3 Leaving the development of smart agriculture as the contribution to the tea industry. Horiguchi Seicha actively takes on the challenge of next-generation agriculture.

Q: From the perspective of smart agriculture, including harvesting robots (unmanned harvesting machines), what do you think tea production sites will look like in the future?

Horiguchi: I think they will become more popular when the manpower shortage and the investment in unmanned harvesting machines coincides and becomes obvious. I think this is a technology that will become widespread in the future.

Horiguchi-san examining a tea farm.

At the moment, there are legal restrictions and field requirements such as someone needing to be nearby to monitor the unmanned harvesting machines. Therefore, we are considering the management of harvesting operations, including transportation methods, while taking these factors into account.

Q: Why are you actively participating in smart agriculture demonstration experiments, which require a lot of effort?

Horiguchi: I think it is important to establish a track record of contributing to the development of smart agriculture by participating in smart agriculture demonstration experiments such as agricultural robotics and local 5G in this region of Shibushi, Kagoshima Prefecture. I believe, that if we can show the value of tea, as one of the agricultural products, from various angles, it will help the tea industry to survive.

Q: What other things besides robotics are you focusing on recently?

Horiguchi: Of course, our company places emphasis on robotics as an initiative, but in the field of smart agriculture, we place the greatest emphasis on digitalization and management visualization.

Horiguchi Seicha is actively working on digitalization.

As the number of people involved increases, the way of communicating and thinking tends to become disjointed. In order to work as a team, we must look in the same direction. To do so, we need indicators and information that enable everyone to look in the same direction, and I believe that digital power will continue to be indispensable for this.

Q: Please tell us about organic cultivation in relation to smart agriculture. What percentage of your production is organic?

Horiguchi: Starting this season, about half of our tea fields (60ha) will be certified organic.

For the past 20 years, we have grown tea at our own tea farm using cultivation methods that do not rely solely on chemical pesticides. However, the current trend is to meet market needs by obtaining organic certification, so the number of certified fields is increasing every year.

Q:Horiguchi Seicha is also a participant in the Rainforest Alliance certification*, right?

Horiguchi: Yes, we have also obtained Rainforest Alliance certification.

* Rainforest Alliance certification: certification is given to farms that meet strict standards for protecting the farm environment, natural resources including soil and water, ecosystems and biodiversity, and providing  the education and welfare of workers including their working conditions, families, and local communities.

Q: How many tea farms nationwide have obtained Rainforest Alliance certification?

Horiguchi: Our company was one of the first in Japan among the tea farms. I think there are still only a small number of farmers working on this nationwide.

Q: Is Horiguchi Seicha focusing on export?

Horiguchi: Yes, there are times when we interact directly with overseas businesses. However, in the majority of cases, we deliver the material tea leaves to domestic wholesalers, and the tea leaves are exported overseas as their products.

We look after the area of 300ha, so we believe it is important to strike a balance between the part we export ourselves and the part exported by our customers who use our tea as material.

Q: What tea cultivars does Horiguchi Seicha handle?

Horiguchi: We have about 20 tea cultivars.

The main cultivars are Yutaka Midori, Saemidori, Asatsuyu, Yabukita, and Okumidori. Although Yabukita is known as the main tea cultivar in Japan, we only grow about 2~3% of it in our tea fields.

Until about 7-8 years ago we had one location with Zairai – native species, but it no longer exists.

Q: Was there always a small amount of Yabukita?

Horiguchi: In the recent replanting, we can say that we are replanting away from Yabukita to other varieties.

Yasuhisa Horiguchi, the creator of Tea Rangers and the father of Daisuke Horiguchi.

However, the reason for the lack of Yabukita is that starting around 2001 and over the period of 10 years, my father expanded the tea farm area to 120 hectares, with about 10 hectares planted each year. And he planted varieties other than Yabukita.

Q: Why did he not choose Yabukita?

Horiguchi: First, even if we did not grow Yabukita  ourselves, there were already many people who were growing this delicious cultivar, so we actively planted new cultivars in search of new flavors.

Another thing is how delicate Yabukita is. Although Yabukita has a very good flavor, it is a delicate cultivar. When we considered the overall situation in terms of disease and pest control, yield potential, harvest time, and other factors in expanding the tea farm, we decided that Yabukita was not suitable for Horiguchi Seicha at that time.

Q: Changing the topic a bit, did you originally aim to expand the area to 120 ha?

Horiguchi: Of course, the demand for tea at that time allowed us to expand to 120 hectares. However, local circumstances were also a major factor.

Pot seedlings of the Seimei cultivar recently purchased from a business partner company.

At that time, our company rented a greenhouse to grow tea pot seedlings. However, in reality, not many farmers purchased potted seedlings, so we decided to plant them ourselves and expanded the tea farm.

Another thing is that originally this area was popular for growing potatoes for shochu (distilled spirit) and creating lawns for golf courses. However, with the bursting of the bubble economy, these industries also suffered, there were quite a few offers from landowners to lease their land for tea farming.

So the times and the local conditions matched, and as a result, our area expanded to 120 hectares.

There are endless ways to enjoy tea. We want to create, communicate, and expand our reach.

Q: What is the future vision of Horiguchi Seicha?

Horiguchi: Rather than further expanding the current tea farm area of 300 hectares, we would like to focus on how to add value to the harvested tea.

Horiguchi-san brewing tea.

We already have a large area for making tea, so we will further fine-tune our tea production there.

For example, there is currently a lot of demand for tencha (tea leaves used to make matcha), but not long ago, demand for tea leaves used for ready-to-drink beverages was growing, reflecting the trends of the time. Although the production volume is small, Japanese black tea is currently attracting a lot of attention as well.

We hope to maximize the overlap between our company’s tea production technology and the needs of our customers.

Q: By the way, you do not produce gyokuro, right?

Horiguchi: Well, I thought it would be interesting to say, “We make everything, except Gyokuro”.

We could make Gyokuro, but then it comes to the question how high the quality of Gyokuro would be. Since we are not making it currently, I do not think there is any need for us to do it.

Since high quality products are already being produced in other regions, such as Yame in Fukuoka, we have decided not to produce it based on current demand as well as our company’s production technology and system.

Q: What does Japanese tea mean to you?

Horiguchi: That is difficult… I would like to see the value of Japanese tea to be better understood in society as a whole. After all, I work with Japanese tea, so I would like to be involved in getting the value of Japanese tea more recognized.

Q: Are there any difficulties in working with Japanese tea?

Horiguchi: I believe that the term Japanese tea has many different elements, and it is difficult to identify which of these elements to properly communicate.

However, more and more people from outside the tea industry are entering it, and I feel that, due in part to their influence, there is no longer a line drawn between the different elements. I think this is a good trend.

I hope that by increasing the number of connections between people who have not been involved in the tea industry, a cycle will be created in which people will learn about values they were not aware of, teach others about them, and spread the knowledge.

Q: What do you think the future of the tea industry will look like?

Horiguchi: I think the current position of Japanese tea is that it has become too integrated into everyday life and has a strong stereotype. I would like to spread the word that there are many other ways to enjoy tea.

Rather than saying things like “You have to make tea in a teapot” or “You have to drink this tea in this season”, I believe that the tea industry will become more interesting if we can convey new ways to enjoy tea and expand the base of tea consumption.

*All photos by Horiguchi Seicha / Wakohen