By Unus Alladin

Rex Tso Sing-yu’s hopes of fighting WBA champion Kohei Kono in December just got tougher after two other top Japanese boxers threw their hat in the ring.

Tso traveled to Tokyo on Monday with his manager, Jay Lau Chi-yuen and strength and conditioning trainer, Jake Verano, to support Kono in the Japanese’s next fight against Panama’s Luis Concepcion, scheduled for Wednesday. Hong Kong’s “Wonder Kid” will try to sway Japanese promoters to make the Kono-Tso showdown happen in Tokyo on December 31.

That December clash depends on many factors, including whether Kono (32-8-1) can successfully defend his WBA title against the 30-year-old Concepcion (34-4-0) in their mandatory fight at the Ota-City General Gymnasium in Tokyo. The bout was ordered because the WBA wanted to consolidate their world champions with regular champion Kono challenging interim champ Concepcion for one unification title.

Tso, the 29-year-old unbeaten super flyweight (19-0-0, 12 KOs), was hoping to sign a contract with Kono immediately after the 35-year-old Japanese veteran retains his title. But the picture has become more complicated with two aspiring Japanese boxers also wanting a piece of the action.

WATCH: Hong Kong boxer Rex “The Wonder Kid” scores 19th straight victory

The two boxers include Takuma Inoue, the 20-year-old younger brother of Naoya “The Monster” Inoue, one of the most well-known boxers in Japan, who currently holds the WBO junior bantamweight belt. Koki Eto, 28, (18-4-1) is the other Japanese boxer eyeing a Kono bout.

The Japanese pair belong to the stable of famed Japanese promoter Akihiko Honda, who also manages WBC flyweight champion Roman Gonzalez, the Nicaraguan superstar (45-0-0) known as El Chocolatito. Honda has promoted many world-class bouts, including one of the most famous of all – James “Buster” Douglas’ stunning upset of Mike Tyson in Tokyo in 1990 – and would want to seal a deal with Kono quickly.

“We are not in an ideal position,” admitted Lau. “We have to compete with two other Japanese boxers because everybody wants a piece of Kono. It’s really up to the promoters and possibly the TV networks to decide which boxer would attract more people to the fight and who would sell more tickets,” he said.

Lau said they had reached a verbal agreement to fight Kono on New Year’s Eve with Kono’s manager, Hitoshi Watanabe, but all that could change if the Japanese promoters decide they want an all-Japanese clash.

“The promoters will have to decide whether they want Rex or one of the Japanese boxers for Kono’s next fight. But we have to remain positive. Rex will be presented in front of the Japanese press for the first time and the Japanese press could be intrigue by Rex, and there’s still a chance we might get the Kono fight. At the moment, the Japanese public doesn’t know who Rex is so we want to make ourselves known to them while we are in Japan,” said Lau.

WATCH: Kohei Kono battles against fellow Japanese Koki Kameda in Chicago last October

“We have only verbally agreed to have Rex fight with Kono with a rematch [clause] in Hong Kong. If we really can’t reach an agreement with Kono, we’ll have to turn our attention away from him and hope Tso can still fight for the world title next year in March for the IBO (International Boxing Organisation) world championship [the newest of the boxing governing bodies].”

Meanwhile, tickets for Tso’s next fight on October 8 during the FIA Formula E Hong Kong ePrix weekend have been selling fast and Lau was confident it will be another sell-out.

“The more expensive tickets [$880, $1,280] have been sold out and we are left with the cheaper tickets [$580, $380]. We are confident of a full house [5,000 seats].”

Rex will begin his training camp on September 4 in Cebu, the Philippines, where he will stay with Verano for one month in preparation for “Battle of Victors” at Wan Chai’s Convention and Exhibition Centre.

“Cebu doesn’t have a conditioning coach so we will send Jake [Verano] to Cebu as well. Rex is looking forward to his training,” said Lau.

Southpaw Tso will be looking for his 20th straight win against another undefeated fighter in 20-year-old Japanese hope, Ryuto Maekawa (11-0-1, 7 KOs), for the vacant WBO international junior bantamweight (115 pounds) title.

It will be Tso’s first fight since his fourth-round TKO victory over former WBC minimum weight world title contender Young Gil-bae of South Korea in May.