Nagase Brothers adopts Azure OpenAI Service for generative AI that could transform practical English learning

Developing English Writing Bootcamp for output-driven English learning

Nagase Brothers opened as Nagase Shingaku Kyoshitsu in 1971. It currently operates various educational businesses, including prep schools for high school students, cram schools, and a business school for working adults. With a philosophy of cultivating independent and confident workers who can contribute socially and globally, it intently nurtures leaders of innovation. Additionally, the company uses AI technology to develop and launch advanced content and services, boasting a top-class history of leveraging AI in education.

“Since the 1990s, we’ve been using IT to provide video classes that can be attended anywhere in Japan,” says Takamasa Yamano, Executive Officer and Deputy of AI Education Development. In 2017, the company launched a program for students to practice subjects based on their universities of choice and began actively adopting AI.

“For the program, we aggregate and analyze the results of students’ mock exams and past questions from their schools of choice,” Yamano says. “We then identify gaps between the student’s strengths and weaknesses and the questions which appear in that school’s exams. AI suggests a set of exercises to fill those gaps, efficiently boosting student pass rates for entering their favorite schools.”

As part of its AI efforts, Nagase Brothers launched English Writing Bootcamp. For this system, generative AI automatically corrects English sentences written by students. Yamano explains the background below.

“We developed English Writing Bootcamp using generative AI in response to changes in high school English education. University entrance exams are transforming to reflect a shift in approach from input to output too. Common entrance exams already reflect the changes. Grading methods remain the same, but the content is more practical.”

Adopting Azure OpenAI Service for swift and stable use of GPT-4

For output-oriented education, students need more English writing experience. However, written compositions are difficult to correct. Nagase Brothers has a full-time team working to correct English essays, but it takes about four days to return students’ work.

“The situation means students only begin writing in English from the middle of their third year of high school, and don’t do so very often,” says Tatsuhito Yoshikawa, who planned English Writing Bootcamp as the Senior General Manager of AI Education Development. Also, the quality of answers is low in the first or second year of high school, so it’s difficult for humans to make corrections.

The appearance of ChatGPT in 2022 would put an end to this headache.

“When I first used ChatGPT, I saw massive potential to achieve things that were previously impossible,” says Takaya Tamura, who planned and developed the English Writing Bootcamp system as Senior General Manager of AI Education Development. “It gave me the idea to use generative AI to correct students’ written English. When GPT-4 appeared in 2023, I knew it would be accurate enough, so I started developing our system.”

Tamura immediately chose GPT-4 due to its colossal capabilities. However, ensuring stable and snappy responsiveness for 100,000 students was a major challenge.

“After investigating request-per-minute processing capabilities, I chose Azure OpenAI Service,” says Tamura. “Azure OpenAI Service guarantees 99.9% availability and has no security issues.”

Tamura designed the system to capably manage large-scale access, balancing loads by combining Azure OpenAI Service across 10 regions around the world.

90% of students want to continue use, a remarkable NPS of 50

In September 2023, just six months after starting development, Nagase Brothers conducted a trial in two Toshin High School locations. After two months of use, many students rated the system as “good.” In January 2024, the company ran a free trial open to anyone, including Nagase Brothers franchises. Additionally, areas in northwestern Honshu, which suffered a devastating earthquake earlier in the month, received the system for free.

English Writing Bootcamp officially released in April 2024. It’s mainly used within the Nagase Group, but high schools can also adopt it if desired. As one example, Tsuhigashi High School in Mie prefecture leveraged the program in 100-minute lessons for summer school. Major media organizations reported on the lessons, attracting a great deal of attention nationwide.

English Writing Bootcamp is divided into five levels: Basic, Basic University Entrance, Standard, Difficult, and Advanced, each with 200 questions. Students select a level, receive a question, and write an answer in English, which generative AI grades on an A-to-E scale. If the grade is B or lower, students receive an evaluation, the correct answer, and advice. Students with A grades see alternative answers instead of advice.

The interface is clean, and corrections are easy to understand. This is because of Nagase Brothers' long-standing expertise in English composition writing. Students are thrilled about these aspects.

“We’ve surveyed students since the trial stage, and 90% of respondents say they would like to continue use,” says Yoshikawa. “In response to the question ‘Would you recommend it to a friend?’ 70% of students give a score of at least nine out of 10. Additionally, the net promoter score (NPS), calculated by subtracting the percentage of detractors (scores of six or less) from that of promoters (nine or more), is remarkably high at 50. We conducted a similar survey at Tsuhigashi High School, and the results were the same.”

Plans for expansion to other subjects

Short correction times are a major reason for the positive reception. Shuhei Kuraoka, who worked on system infrastructure as a manager in AI Education Development provides more details below.

“Distributing load across multiple regions makes it much faster than OpenAI’s GPT-4. Even during evening peaks when most students use the system, the response time averages 20 seconds.”

Nagase Brothers currently balances loads by combining multiple endpoints but may introduce Azure API Management to measure loads and response times in each region to further optimize distribution. According to Tamura, Azure provides the flexibility to do this without any programming.

“We’re also considering a service to evaluate students' English pronunciation based on Azure's speech-to-text conversion function,” said Kuraoka. “Azure is currently the only service that has an API to extract phonemes from speech and evaluate pronunciation.”

“In the future, I’d like to expand our scope of application to subjects beyond English writing,” says Yamano. “In August 2024, we launched, ‘Information I -Programming Bootcamp,’ which provides 1000 programming exercises and automatic correction. With immediate corrections from generative AI, you can learn something substantial in a short amount of time. This has the potential to significantly change practical learning.”