Kobayashi, a six-time world hot dog eating champion from Japan, consumed 5¾ P'zones in a six-minute span of chaotic consumption Saturday to edge Chestnut. The 25-year-old from San Jose, wolfed down 5½ P'zones on Stage 15 at Sony Studios.
"I'm a little bummed," Chestnut said. "There's nobody I like beating more than him, he pushes me harder than anybody."
The arch rivals are best known for their annual Fourth of July hot dog eating showdowns on New York's Coney Island. Chestnut has beaten his Japanese competitor the last two years, winning last year in a five-dog eat-off after they tied at 59 frankfurters in 10 minutes.
This time, they went cheek-to-jowl in a stomach-centric contest sponsored by Pizza Hut featuring the P'zone, a pizza weighing one pound with pepperoni and other ingredients sealed inside a crust. At nearly 12 inches long, it resembles a calzone.
Jaw strength and stomach capacity were sorely tested in consuming one of the most filling foods on the competitive eating circuit.
A serious-looking Chestnut prepped by opening his mouth wide and loosening his jaw. Kobayashi stretched his lean limbs and whispered with his interpreter.
Then it was time.
Chestnut took an early lead, squeezing a P'zone in his left fist while alternately slugging from a water bottle. Soon, liquid splashed all over Chestnut's white jersey and dripped from his mouth.
Kobayashi took a tidier approach.
He roared back to take the lead for good on his second P'zone, tearing off bites of the golden crust, then folding it over and sipping carefully from a series of white paper cups that he refilled with water.
"The crust was very chewy so my technique was to try to drink as much water as possible to soften up the crust in my mouth," Kobayashi said through his translator.
No dunking was allowed, and containers of marinara sauce accompanying each P'zone were tossed aside by both chowhounds.
A small crowd gathered a few feet from the elevated food fest cheered the men on, with Chestnut's highway patrolman brother yelling inches from his face to eat faster.
Chestnut couldn't keep up with his 31-year-old rival from Tokyo.
At the six-minute mark, Kobayashi raised his arms in triumph and lifted his red jersey to show off a set of washboard abs.
"It was tough. Kobayashi came to win," Chestnut said. "I was raised on pizza so it was natural for me to eat it, but I was a little slow to get going and he came out fast."
The thought of a Japanese outeating an American in a pizza contest wasn't lost on Kobayashi, who is recovering from TMJ, a painful jaw disorder.
"I love pizza," he said. "When I come to America, pizza is my happiness. I look forward to eating it."
Chestnut said he wasn't used to eating pizza that quickly.
"It's doughy," he said. "It takes a lot of chewing. He got off to a really good technique early on, his rhythm was drinking water and swallowing. I changed mine a couple times and never got in the right rhythm."
Kobayashi ended a three-event losing streak to Chestnut, a 25-year-old whose weekday job is in construction management.
"I wanted to prove that I'm champion," Kobayashi said. "A champion will stand up to any battle."
He said he would go for another Fourth of July hot dog championship and then probably retire. Chestnut will be ready and waiting on Coney Island.
"I'll see him in five weeks and I'm going to push him really hard there," he vowed.
Portions of the pizza event will air on the Spike TV "Guys' Choice" show on June 21.