Picture a kid in October 1985, unwrapping a new NES. The box promises Donkey Kong Jr., a character they already know from the arcade. What’s inside is a math worksheet with a vine-climbing monkey attached to it.
Donkey Kong Jr. Math hit North American shelves on October 18, 1985, the same official NES launch day as Super Mario Bros., Duck Hunt, and Wrecking Crew. It was built by Nintendo’s own R&D2 team, designed by Toshihiko Nakago, and it recycled the engine, backgrounds, and sprites from the 1982 arcade game almost wholesale. Nintendo just swapped the goal. Instead of climbing to rescue your father, you climb to collect digits and operators that solve the equation Donkey Kong is holding up. A second mode drops the platforming entirely and turns the chains into a flashcard drill. One or two players, your choice of torment.
Nintendo had bigger plans for this than a single oddity. Donkey Kong Jr. Math was meant to launch an “Education Series,” with a companion music game called Donkey Kong’s Music Play waiting in the wings. That second game never came out in the US. The first one barely needed to.
Bruce Lowry, Nintendo of America’s sales VP at the time, put it bluntly years later: it was the worst game the company ever sold. Retailers couldn’t move it even with the full weight of the NES launch behind it. Wikipedia’s rundown of the game notes it quietly sold better in Japan, where it had launched two years earlier on the Famicom, but in the US it got discontinued by May 1988 and mostly disappeared from memory. Critics who revisited it later weren’t kind, either. Nintendo Life handed the 2007 Virtual Console re-release a 1 out of 10.
Here’s the twist collectors already know. A game nobody wanted in 1985 is exactly the kind of game that’s brutally hard to find a complete copy of in 2026. Short print runs plus low demand plus three decades of attics and landfills adds up to a population report with barely a handful of graded copies on record, and none of them sealed. That scarcity is why a Wata 6.5 CIB copy sold at Heritage Auctions for $1,937, a number nobody would have guessed while the cartridges were gathering dust on clearance racks. We’ve written before about how a thin production run turns a flop into a safe bet for graders, and this is about as clean an example as the NES library has to offer.
It also belongs to a small, strange club of launch titles that got buried the moment flashier games showed up next to them on the shelf. If you want to see where Donkey Kong Jr. Math fits among Nintendo’s other 1985 launch cartridges, our ranking of the ten best NES Black Box games covers the rest of that opening lineup, and our look at the NES port of the original Donkey Kong explains how Nintendo kept squeezing new cartridges out of the same arcade hit that same year.
The game didn’t vanish entirely. It popped up as a cameo in Animal Crossing in 2002, got reissued on the Wii and Wii U Virtual Console, and landed on Nintendo Switch Online in 2024, which means you can now play the worst-selling NES launch game on hardware that costs more than every copy Nintendo couldn’t give away combined. If you’ve got a sealed or near-mint copy sitting in a closet, it might be worth more than you think. Check our gallery of graded cartridges to see what condition actually does for a price tag like this one.