Ask Kei Tanaka, Mariko Mabuchi, and Testa: My view on money

How you deal with money reflects your lifestyle and values. We spoke to three people who have been gaining attention in recent years for their money sense in various fields, and they share their stance on money and tips on how to deal with it.

This article is a special release from BRUTUS's "Getting Started with Money" (released January 13, 2026). For more details, click here.

illustration: Keiko Ogawa / text: Koji Okano

[Listener]
Kei Tanaka (Investor, Radio Personality)
Mariko Mabuchi (Economic analyst, Visiting Associate Professor at Osaka Municipal University)
Tester (Investor)

Who do you consider to be your financial mentor?

Kei Tanaka

History and market price.
The philosophy of all money gurus is wisdom gained from studying market movements and the history of the financial and stock industries. Therefore, I believe that I have acquired financial literacy by studying the market and history itself.

Mariko Mabuchi

Economist Toshihiro Nagahama.
Nagahama-san conducts data-based economic analysis, placing the primary focus on how Japan can improve. I look at the economy every day with the same mindset, so I have a lot of respect for him as a senior.

Tester

My mom.
"When you want something, save up twice as much money before buying it." This is a motto my mom told me when I was in high school, and I still live by it today. By the way, when I was in high school, what I wanted was just ordinary things like video games.

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What's the best way to spend money in life?

Kei Tanaka

Spending money on others.
There is a young political party that I want to support in the 2025 House of Councillors election, so I made my first political donation. I've also recently been focusing on angel investing. Investing in young people who are taking on challenges has become a rewarding way for me to spend my money.

Mariko Mabuchi

Time spent with loved ones.
I want to enjoy life with everyone, so I don't have much of a desire to save money. I think happiness comes from spending it all before you die. For example, I spend money on going out to eat or spending time with the people I care about.

Tester

Donations to children's homes.
Spend your money first on yourself, your family, and your loved ones. Donating after that is proof that you have the financial means to do so. I think this is the best way to spend your money and feel like you've grown as a person.

Illustrations for economic analysis materials

How to turn 1 million yen into 100 million yen as quickly as possible?

Kei Tanaka

Sell your own content. I will compile the content I have accumulated into a note every week and get 10,000 people to subscribe for 1,000 yen a month. I will spend 1 million yen on advertising.

Mariko Mabuchi

Invest in yourself. I think the thing that can be leveraged the most is the human being. If you had 1 million yen, you could use it to somehow increase your value, to develop the strengths that everyone has, and the money would come later.

Tester

First, let go of the idea of being the fastest.
If you're aiming for the fastest return on your stock investments, the standard strategy is to use leverage, increase your bet amount, and try to increase your profits all at once. However, this will very likely result in you losing your original 1 million yen. If you're trying to get 100 million yen through investing, you should change your mindset from "fastest." Steadily increasing your profits will give you the chance to continue growing even after you reach 100 million yen.

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