Professor Koji Wakayoshi of the Faculty of Human Sciences to Teach "Safe Swimming Class" to Elementary School Students, Fostering Thinking and Judgment Skills with the "Da no Ji" Swimming Method

July 6 (Mon) Zeze Elementary School, Otsu City, 5th Grade (Keihan Ishiyamah Sakamoto Line "Nakanosho" Station)

Periods 1 & 2 (8:35-10:10) / Periods 3 & 4 (10:30-12:05)

Osaka University of Economics (President: Shunichiro Yamamoto / Location: Higashiyodogawa Ward, Osaka City) announced that Professor Koji Wakayoshi of the Faculty of Human Sciences will provide practical instruction in the safe swimming method "Da no Ji" on July 6 (Mon) at Zeze Elementary School, Otsu City.

The polarization of children's swimming abilities, reduction in instruction time, and teachers' anxiety about swimming instruction. What is required of school swimming classes?

Every year, water accidents in oceans and rivers continue to occur. While swimming is considered a "life-critical learning" in school education, school swimming is currently at a major turning point. It faces many challenges, including the polarization of swimming abilities and motivation gaps due to swimming experience, teachers' anxiety about swimming instruction, and reduced instruction time due to extreme heat, making it difficult for children to master swimming techniques through uniform instruction.

Professor Wakayoshi, a member of the Japanese national water polo team for the Olympics, believes that school swimming needs to enable children who cannot swim to feel "capable" and allow children who can swim to "continue learning." To address this, he developed the safe swimming program "Da no Ji" (Big Letter Method), which allows all students in a class to learn together regardless of their swimming ability.

Children who can't swim feel "capable"! Professor Wakayoshi practices a swimming class at an elementary school that leaves no one behind

School swimming is expected to provide instruction in basic skills and knowledge for interacting with water and protecting oneself, such as floating, breathing, and moving in the water. This summer, Professor Wakayoshi will travel to Osaka, Shiga, and Wakayama to provide instruction in the safe swimming program to elementary school students and teachers.

The "Da no Ji" swimming method program, developed and promoted by Professor Wakayoshi, begins with mastering "Da no Ji Uki" (Big Letter Float). This is the fundamental posture for "not expending energy (panicking), moving to a safe place, and floating to wait (for help)" when caught in a water accident. However, instantly adopting the "Da no Ji Uki" posture requires familiarity and training.

In the class at Zeze Elementary School, 5th graders will use "Flat Helper," a swimming aid made from buoyancy materials such as plastic bottles and kickboard material.

"Flat Helper" works by inserting buoyancy materials, such as inflated plastic bottles, into pockets on both sides of a net-material auxiliary pants, which helps to support the buoyancy of the lower body, which tends to sink, and makes it easier for the body to float. Even children who cannot swim can easily acquire the sensation of "floating" by wearing this.

Following this, the class will aim to master the "Da no Ji" swimming method together, practicing floating, sinking (diving), and moving with flutter kicks.

In addition, the class will practice a scientific approach to how to float by adjusting the air in the plastic bottles according to one's own weight and swimming ability. By removing the plastic bottles and reducing buoyancy, students will also experience the difference in floating between the ocean and lakes/rivers.

Otsu City Zeze Elementary School Swimming Class Overview

Date and Time: July 6, 2026 (Mon) 8:35 AM - 12:05 PM

Location: Zeze Elementary School, Otsu City (Address: 2-8-37 Nakanosho, Otsu City, Shiga Prefecture)

Instructor: Koji Wakayoshi, Professor, Department of Human Sciences, Faculty of Human Sciences, Osaka University of Economics

Content: Swimming class to foster thinking and judgment skills (Environmental education + Safe swimming + Technique acquisition)

Acquisition of the "Da no Ji" swimming method for safety.

Participants: Approximately 115 students in 4 classes of 5th grade

●Periods 1 & 2: 5-3, 5-4 (57 students)

●Periods 3 & 4: 5-1, 5-2 (58 students)

Instructional Assistants: 4 teachers from Zeze Elementary School, Otsu City (2 per session)

≪Koji Wakayoshi Profile≫ https://webj8.osaka-ue.ac.jp/ouehp/KgApp?resId=S000178

Professor, Department of Human Sciences, Faculty of Human Sciences, Osaka University of Economics.

As an expert with knowledge of swimming research, practical application, and competition, he is conducting research to transform school swimming through science.

Professor Wakayoshi participated as a athlete in the water polo competition at the 1984 Los Angeles Olympics. Since then, he has been involved in swimming from both competitive and research perspectives, and has been active for over 20 years as a member of the Japan Swimming Federation's Sports Science Committee and Science Committee.

While continuing research and instruction for a wide range of individuals, from swimming beginners to Olympic athletes, he has focused on the issue of "school swimming that leaves behind children who cannot swim." He aims to achieve swimming education where beginners can experience "floating and moving," thereby improving the efficiency of beginner instruction, solving problems in school settings, and realizing a society where everyone can swim – "National Swimming for All."

Reference: School Swimming Project https://gclab.jp/school/

About the "Da no Ji" Swimming Method

Program Content

1 Safe Swimming (Water Accident Prevention)

- Acquire basic skills for safe swimming to protect oneself from water accidents.

- Conduct "Float and Wait" training. The basis of the "Da no Ji" swimming method is the "Da no Ji Uki" (Big Letter Float). This posture has been found to be very effective in developing a sense of water.

- It takes familiarity and training to be able to adopt this posture instantly. Furthermore, from this "Da no Ji Uki," we work on acquiring swimming techniques for safe swimming.

- Also, natural rivers and oceans do not have walls like swimming pools. Therefore, practice will be conducted to return to the original position while floating without pushing off a wall.

- Practice using the Flat Helper allows students to learn a horizontal posture.

2 Environmental Education

- The Flat Helper is normally used with pads, but it can also be used with plastic bottles inserted.

- Generally, students learn about environmental destruction by plastic bottles and the current state of recycling.

- Here, it is linked to environmental education as a comprehensive learning experience. Using buoyancy aids such as kickboards and plastic bottles, students experience the difference in buoyancy between fresh water and saltwater (rivers and oceans), which is not usually possible. In seawater, one gains about 2% to 2.5% of buoyancy relative to body weight. For a child weighing 40 kg, this is equivalent to the buoyancy of about two plastic bottles.

3 Technique Acquisition

- This is performed using the Flat Helper.

- Following the safe swimming sequence, students will aim to acquire techniques such as sinking, floating, different ways of floating (prone float <=> back float), methods of propulsion (e.g., butterfly stroke), and swimming techniques.

- By alternating between swimming crawl stroke and "Da no Ji Uki" for a certain period, the aim is to acquire swimming techniques in a short time.

* Depending on swimming ability, combinations of glide and "Da no Ji" or crawl stroke and backstroke can also be used.

Development: Koji Wakayoshi, Professor, Department of Human Sciences, Faculty of Human Sciences, Osaka University of Economics

≪About Flat Helper≫

- Flat Helper is a swimming aid that allows users to learn the "correct posture."

- It uses buoyancy material made of kickboard material. 500ml plastic bottles can also be used as buoyancy material.

- It helps improve posture issues such as difficulty with breathing during crawl stroke, sinking hips during backstroke, difficulty with breaststroke kick, and sinking hips and experiencing resistance during butterfly stroke, thereby aiding in the acquisition of swimming techniques.

* The photo shows the use of kickboard material as buoyancy material.

Osaka University of Economics

▼Contact Information for this Matter: Osaka University of Economics, Planning and General Affairs Department, Public Relations Office Address: 2-2-8 Osumi, Higashiyodogawa Ward, Osaka City, Osaka Prefecture TEL: 06-6328-2431 E-mail: kouhou@osaka-ue.ac.jp