YOKOSUKA NAVAL BASE, Japan — When Alex Trebek, host of one of the world’s most popular trivia shows, gives you test advice, you take it.

“You have to be well-read and up on what’s happening in the world,” Trebek said Thursday at Yokosuka Naval Base as hundreds of people lined up to take a crack at being a contestant on “Jeopardy!”. “I always tell people that the hardest category on ‘Jeopardy!’ is the one you don’t know.”

Trebek, along with other show staff and USO/Armed Forces Entertainment, were scouting for players and showing support at bases in Japan and on Okinawa this week. This is Trebek’s 12th USO tour. Beyond making tryouts “convenient” for military and their families living abroad, Trebek feels strongly that the troops shouldn’t be “forgotten” in peace or wartime, he said.

Fun games and autograph sessions were held for casual viewers, and those who want to compete take a 10-question pretest, which determines whether they can take the 50-question final test. Those who pass the final test can be considered as an actual television contestant.

There’s no harm in taking the pretest, Trebek said. After all, the “Titan of Trivia” took the pretests himself for 16 years before job security caught up with him, he said.

“I passed them all,” Trebek said. “But then I stopped taking them when I realized ‘I got the job. I don’t have to worry.’ ”

Trebek, 67, has hosted “Jeopardy!” for 23 years. The show touts itself as “the most difficult game show on television” and has 32 million viewers, according to the “Jeopardy!” Web site.

More than 200 people took the “Jeopardy!” pretest at Naval Air Facility Atsugi on Wednesday. Forty people went on to take the 50-question final test, which five passed, according to Donna St. John, USO vice president of communications.

At Yokosuka on Thursday, prospective military and civilian contestants lined up at Club Alliance.

“I just wanted to see if I could compete,” said Petty Officer 2nd Class Jeff Behimino. “I didn’t expect to see a poetry question.”

“I love Jeopardy, so I thought I’d check it out and see what happens,” said Navy spouse Laurie Cuddington, who made it to the next round.

The pretest was “harder than she thought,” but she would take the final test, she said.

The two-hour final test can be more difficult than doing the show, Trebek said.

“The final test has 50 categories versus 13 on the show — if you pass the test, then you have a fairly broad base of knowledge,” he said.

But many just came to see Trebek, who has become an American television icon. Trebek signed autographs (including on a pair of shoes), held babies and donned ballcaps for those who came to meet and have their picture taken with him.

Twenty-two-month-old Sydney McDonald recognized Trebek, as she has been a “Jeopardy!” fan since she was 15 months old, said her mother, Tammy.

The toddler likely is a future contender, she said.

“Sydney goes right to the television when it’s ‘Jeopardy!’ time and sings the theme song,” Tammy said. “I guess there are worse things to watch than historical trivia.”

Next stop: Okinawa

“Jeopardy!” was to be at Kadena Air Base on Saturday. The pretest for Okinawa status-of-forces-agreement personnel, mock game and autographs was set for 3-5 p.m. at Schilling Community Center. The show will be at Camp Kinser on Sunday, with a mock game and autographs starting at 1 p.m. at the Surfside. The final test for Okinawa hopefuls will be given at 5 p.m.

Prospective contestants must be status-of-forces-agreement sponsored and 18 or older.