ジェーン・スー 生活は踊る · Society & Culture
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Ahead of the following week's 'Onigiri Week,' Jane Su: Seikatsu wa Odoru (ジェーン・スー 生活は踊る) ran a live taste-test of ten different toppings on tuna mayo onigiri. The hosts worked through combinations ranging from umeboshi and takuan to taberu rayu and cheese, zeroing in on tuna mayo's core weaknesses — monotonous texture and a vague, flat flavor — and hunting for the toppings that fix them. Three winning combinations emerged, including a late-session discovery that Sue compared to Spanish pintxos.
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What this episode answers
When and how did the tuna mayo onigiri originate?
Seven-Eleven launched it in 1983 — the first convenience-store tuna mayo onigiri. The idea reportedly came from seeing a child of a business partner's product developer eating rice topped with mayonnaise; it was shocking at first but gradually became a staple.
How many toppings were tested, and what were they?
Ten toppings in total: six requested by Sue (umeboshi, takuan, wasabi soy sauce, kimchi, taberu rayu, and cheese) plus four prepared by the show (shio kombu, shiso, age-dama, and miso), each tested alone or in combination.
What are tuna mayo's 'weaknesses,' and which toppings addressed them?
The two weaknesses are monotonous texture and a vague, flat flavor. Takuan and age-dama supplied crunch to address the texture issue, while umeboshi, kimchi, and shiso — through acidity and aroma — sharpened the flavor.
What were Sue's and Ugajin's respective best combinations?
Ugajin's best was shiso + takuan, which they dubbed the 'Golden Triangle.' Sue's best was umeboshi + shiso. A late-session combo of age-dama + shiso + black pepper was singled out by Sue as rivaling Spanish pintxos.
If you want to upgrade a tuna mayo onigiri at home, what should you add first?
Both hosts recommend starting with age-dama, then adding shiso; together they tackle both weaknesses at once, and a small amount goes a long way.
The Surprising History of Tuna Mayo
As Ugajin (宇賀神) explained, the tuna mayo convenience-store onigiri was first sold by Seven-Eleven in 1983 — a fact documented on the chain's 50th-anniversary website. The origin story is surprisingly domestic: a child of a business partner's product developer was spotted eating plain rice topped with mayonnaise, and that image sparked the idea. The 'mayo-on-rice' concept caused something of a shock when it hit shelves, but it built a following steadily and eventually became one of the most iconic onigiri fillings, opening the door for other unconventional ingredients along the way. Sue noted that tuna mayo didn't exist when she was a child, and found herself genuinely surprised by how recent that history is.
The Test: Ten Toppings
The studio was laid out with a base supply of tuna mayo onigiri and two sets of toppings: six chosen by Sue (umeboshi, takuan, wasabi soy sauce, kimchi, taberu rayu, and cheese) and four sourced by the show (shio kombu, shiso, age-dama, and miso), ten in all. The production staff had made a large batch of small onigiri — enough for rapid back-to-back tasting — and both hosts agreed the spread looked almost too cute to eat, with Sue saying she wanted to photograph it. From there, Sue and Ugajin worked through each topping individually, then began combining them.
Tuna Mayo's Weaknesses Come Into Focus
As the tasting progressed, two recurring problems with tuna mayo became clear: monotonous texture and a vague, flat flavor. 'Tuna itself is soft and heavy, so the texture gets boring,' Sue said. Taberu rayu helped with its crunchy garlic chips; takuan helped with its firm, snappy bite. On the flavor side, umeboshi and kimchi both introduced acidity that seemed to pull the tuna mayo into sharper focus. Shiso earned praise early in the session for the way its aroma traveled through the nose, and the verdict that 'shiso and tuna mayo work together' was locked in before long. Wasabi soy sauce got a more pragmatic reaction from Sue: 'That's just a tuna mayo gunkan from a sushi restaurant — of course it works.'
The Best Combinations
After working through all ten options, the hosts settled on three standout combinations.
**Shiso + Takuan (Ugajin's pick)** The shiso aroma and takuan crunch complement each other so well that they named the pairing the 'Golden Triangle.' It balances texture, fragrance, and a gentle acidity in a way that feels complete without being complicated.
**Umeboshi + Shiso (Sue's pick)** The acidity of the umeboshi tightens up tuna mayo's flatness, and the shiso ties everything together. Sue summarized her overall takeaway from the session as 'acidity and bite are what matter,' and this combination embodied that conclusion most directly.
**Age-dama + Shiso + Black Pepper (the late-session discovery)** Adding age-dama gives the onigiri a snack-like quality — crunchy and a little oily in a satisfying way — the shiso keeps it fresh, and the black pepper pulls the whole thing into a coherent finish. Sue said calling it Spanish pintxos would not be an exaggeration. Both hosts agreed it felt cohesive and remarkably filling.
Adapting This at Home
The practical conclusion from the session: 'Start with age-dama, then add shiso, and from there the world opens up depending on what you like.' A few individual notes also came out of the discussion: cheese and shio kombu work reliably together because of an affinity between the two dairy-adjacent ingredients; miso can pair well with tuna mayo but needs to be used in restrained quantities or it overwhelms everything else; and kimchi, while effective on its own for adding acidity, actually balances better when paired with age-dama than when used alone. Both hosts agreed that eating tuna mayo onigiri straight, without anything added, is a missed opportunity — a small addition is all it takes to move it into a completely different league.
Takeaways
- The tuna mayo onigiri was invented by Seven-Eleven in 1983, inspired by a child eating rice with mayonnaise, and grew from a novelty into a convenience-store staple.
- Tuna mayo's two core weaknesses — monotonous texture and flat flavor — can be fixed with crunch (age-dama or takuan) and acidity or aroma (umeboshi or shiso), with shiso appearing in all three of the session's top-rated combinations.
- The highest-rated home upgrade is to add age-dama first, then shiso, and optionally black pepper — a combination both hosts described as rivaling Spanish pintxos in satisfaction.
This article is edited from a machine transcript of the first 30 minutes of the episode. It is not an official summary — please listen to the episode itself.