Shark Damage Reduction Equipment


What is Kaien?

This device stimulates the Lollentini organ, an electrical sensing organ located on the tip of the nose of sharks and rays, by generating a small electric current on the surface and in the water that sharks dislike, thereby triggering the sharks’ avoidance behavior.

The use of this product can dramatically reduce damage caused by sharks and rays by using it for fishing damage caused by sharks, accidents involving surfers and swimmers, and in the life jacket field.


Enjoy fishing without thinking about the damage caused by sharks!


Shark Avoidance Rate *1

Kaien Users/year *2


Customer Satisfaction *3

*1 Demonstration by our staff in Sagami Bay: 65 out of 72 hits were avoided (2022)
*2 Actual results for FY 2022
*3 At Sagami Bay, from a post-use questionnaire

What’s new!

Regarding Product Delays

Currently, due to the worldwide shortage of semiconductors and the effects of the new coronavirus infection, there are significant delays in the delivery of electronic components used in our products.
We are attempting to arrange for parts as much as possible, but supply is not keeping up with demand, and we are receiving last-minute delays and undecided delivery notices.
As a result, we are unable to deliver our products, “KAIZEN series,” on time as expected by our customers.
We will continue to work proactively to keep in close contact with our suppliers and consider alternatives for parts, but the situation remains uncertain.
We deeply apologize for any inconvenience this may cause, as we are in the middle of the tuna season in Sagami Bay.
We will continue to do our utmost to ensure a stable supply of our products, and we appreciate your kind understanding and cooperation.

Kaien Products


Kaien Diving

Kaien Diving (海園ダイビング)
Kaien Diving
Kaien Diving

Kaien Diving (for Divers)

Two Kaien tech with “patented technologies” are inside

Kaien Fishing


Kaien Fishing (for Anglers)

Splendid Alfonsino

Tuna Ring attached with Kaien

Kaien Forming

Kaien Forming (for Aquaculture)


Does Kaien work effectively? See the experiment here!


Thanks to your help last year, I was able to catch a yellowfin that weighed just under 27 kg! Thank you very much.

Sagami Bay

Thanks to Kaien, a total of 7 lingcod were safely on board from the first cast 😊.

Shimoda Bay

Every year we were plagued by sharks, but since using Kaien, we no longer lose money due to sharks.

2021 Sagami Bay

We are safely fishing for tuna.

2019 Sagami Bay

We will use Kaien again this year!

2022 Sagami Bay


Kaien Diving
Kaien Diving (for Divers)
Kaien Forming (for aquaculture)
Kaien Fishing (for Anglers)

Reducing shark damage from fishing

Tuna Ring Attachment

Attach to tuna rings to reduce shark damage.
Click here to see more details about Tuna rings & attachments


We will continue uncompromising development to achieve coexistence with sharks.

Due in part to the warming trend, shark damage has been reported throughout the country.


For example, damage to anglers’ catch, fishermen’s catch and fishing gear, or damage to nets in aquaculture fish ponds.

Current shark control measures include,

– Exterminate sharks
– Entering a dedicated cage to avoid direct damage.
– Stop the operation and get out of the water.

Currently, sharks are being removed from the water by means of a special cage to avoid direct damage.

There is also concern about the negative impact on the IUCN Shark Specialist Group’s Red List of Threatened Species (17 of the 58 shark species).

-Mark Specialist Group

What if there was a way to keep sharks away?

KAIEN’s technology makes it possible to avoid harm to sharks.

Since 2013, we have been conducting a series of demonstration tests, and after the “KAIEN” for fishing, we are now working hard to expand the technology to other fields such as “diving” and “aquaculture”

Please visit our YouTube page to experience the effects of KAIEN.

Please let us know what you think too

About Company


We are constantly aiming to work on development to further improve the technology of the Kaien and its diversion to fishing and leisure activities.


Hanazono Co., Ltd.

President and CEO

Satoshi Nagoya


950-3, Makishima-cho, Nagasaki 851-0114, Japan


A device for repelling sharks and other underwater creatures that cause human damage or feeding damage, and its method of use.
Patent No. 6582307(Acquired on September 13, 2019)

Electronic Equipment and Electric Field Barrier Type Device.
Patent No. 7291364 (Acquired on June 7, 2023)

Fishing Aids and Apparatus to Prevent Fishing Injury from Sharks and Other Injurious Species.        Patent No. 7351519 (Acquired on September 19, 2023)

Electronic Equipment and Magnetic Field Barrier Formation Device                
Patent No. 7356768 (acquired on September. 27, 2023)

JPB 007291364-000000
Patent No. 6582307
(Acquired on Sep. 13, 2019)
Patent No. 7291364
(Acquired on Jun. 7, 2023)
Kaien patent
Patent No. 7351519
(Acquired on Sep. 19, 2023)
Patent No. 7356768
(Acquired on Sep. 27, 2023)

“How can shark damage be prevented in fishing?”

It has been about 7 years since the idea was conceived.

After much original research and improvement, we obtained a patent on September 13, 2019.

We are now developing products that can be used not only for fishing but also for fishing and a wide range of marine leisure activities.
We are now developing products that can be used not only for fishing but also for fishing and a wide range of marine leisure activities.