12:00 P.M. Decamps to Christie’s headquarters in Alexandra House, where Sue Tsao, an L.A.-based jewelry collector from Taiwan, is looking at a green diamond with Vickie Sek, the director of jewelry and jadeite in Asia. “Ken is so spoiled,” Sek teases. “He always demands the best food, the best art.” Yeh points out that a lot is at stake: His clients “will pay $5 million to $10 million for a work on my recommendation.”

1:05 P.M. Navigates a labyrinth of footbridges to take Tsao to lunch at L’Atelier de Joël Robuchon. They perch on stools at the gleaming black-marble-topped bar. “I prefer to sit up here so I can watch the cooking,” he says.

2:45 P.M. Back in the Mercedes, phones a customer in Taipei to remind him about the previews on Saturday. “My clients are very busy people,” he says. “Even if they plan to attend, I always follow up the day before or on the day to encourage them to come and take a look.”

2:55 P.M. His BlackBerry beeps. “Oh dear, they want me to give a talk in Shanghai next month.” He punches out a reply.

3:03 P.M. Richard Ho, a local businessman who’s a longtime friend and client, ushers him into a boardroom overlooking the Wanchai harbor front. Although Ho collects mainly antique Chinese arts and crafts, Yeh is “cultivating” him in more modern Chinese works. “I want you to find me the next Yue Minjun,” quips the dapper Ho, referring to the record-breaking Chinese artist.

4:03 P.M. Back in the car, squeezes in two phone calls before returning to Christie’s, where he sits down at the desk in his medium-size corner office, which is decked out in traditional Chinese wood furniture. Gulps down a glass of water and checks his e-mail.

4:32 P.M. The office phone rings, heralding his appointment with Jonathan Stone, who works with Yeh, handling the day-to-day business of Christie’s Asian art department internationally. Stone updates Yeh on Christie’s planned expansion of its auction space at the Hong Kong Convention and Exhibition Center. Everyone is happy, but Yeh notes that “the budget needs to be controlled.” Stone promises to follow up.

5:00 P.M. Eric Chang, head of 20th-century Chinese and Asian contemporary art, knocks on the door to discuss progress on this May’s Hong Kong sale.

6:30 P.M. Breezes into an in-house cocktail party and warmly greets participants in Christie’s yearlong Leadership Programme, designed to train staff members from around the world to be the firm’s future leaders.

7:04 P.M. Dashes out of the office. As he is on his way to the elevator lobby, a colleague pops her head out of the door and shouts after him in Mandarin. She wants to make sure he has enough business cards for tonight. Checks his pockets; there are plenty. “Thanks,” he calls back.

7:14 P.M. At the entrance of Kee, double-checks the guest list—a mix of VIP and prospective clients and A-list society names—before accepting a flute of Perrier-Jouët Champagne. Spends most of the evening talking to potential customers. “A lot of people feel Impressionism’s for older collectors, but it’s not true,” he says. “If there are collectors in their 30s in Europe, Taiwan and mainland China, why not in Hong Kong?”

8:30 P.M. With the party in full swing, engages in conversation with the ceo of a European luxury-goods company who is particularly interested in Miró’s La caresse des étoiles, 1938, estimated at $16 million. Yeh grows animated. “Would you believe this was first sold in exchange for a coat?” he asks, relating how the artist’s dealer gave the picture away after the liberation of Paris, in 1944. Exchanges business cards with the CEO and invites him to preview the other highlights at the Grand Hyatt over the weekend. “I’ll call him on Friday and ask him to pay a visit,” Yeh says. “Hopefully something will catch his eye.”

10:45 P.M. Guests drift away from the exhibited works on Kee’s first level, lured to the upstairs dining area by caviar-topped baby blini and other dainty nibbles. Yeh stays downstairs with his colleagues and the Kee Club’s owners, Maria and Christian Rhomberg, who order a late supper of fried rice noodles, roast duck and roast goose from Yung Kee, the renowned Cantonese restaurant next door. Yeh eats the food gratefully.