Japan Prime Minister Shinzo Abe on Wednesday appointed new foreign and defence ministers and promoted a popular rising political star, in a cabinet reshuffle that fuelled speculation over the prime minister’s successor.

The spectacular appointment as environment minister of the telegenic Shinjiro Koizumi, the 38-year-old son of much-loved former PM Junichiro Koizumi, set tongues wagging in Tokyo political classes as the Abe era draws to a close.

Koizumi was one of 13 first-time ministers among 19 whose appointments were announced by Chief Cabinet Secretary Yoshihide Suga. At 38 years old, Koizumi becomes the third-youngest to win a portfolio in post-war Japan, local media said.

“Abe intends to start an open race to pick the next prime minister or even the one after that,” said SMBC Nikko Securities chief market economist Yoshimasa Maruyama.

Abe is set to become Japan’s longest-serving prime minister in November but is expected to step down at the Liberal Democratic Party (LDP) leadership election in 2021 and the jostling for position is already beginning.

Japan’s new foreign minister is Toshimitsu Motegi, who was promoted as a reward for his work in negotiating a trade deal with the United States.

Despite drafting more than a dozen new faces, Abe retained his close allies, Finance Minister Taro Aso and Suga. Both have served in their posts since Abe returned to office.

“It looks like the ultimate buddy-buddy Cabinet. He’s shuffling the same people around, with only those with good ties with Abe joining”, said Norihiro Fujito, chief investment strategist at Mitsubishi UFJ Morgan Stanley.

Another Abe ally and potential future prime minister, former health, labour and welfare minister Katsunobu Kato, returned to his old post.

PM Abe’s task was hectic when his LDP-led coalition lost its two-thirds majority in a July upper house election. Amendments to the charter require approval by two-thirds of each chamber of parliament and a majority in a referendum.