David Kaplan's Alfresco Kung Fu in Chinatown Julia Gillard for The New York Times David Kaplan with one of his students in Columbus Park in Chinatown, where he teaches his pay-what-you-can classes six mornings a week, rain or shine. ON a recent Saturday morning, I joined eight kung fu students and their master, David Kaplan, in Chinatown for a lesson in martial arts. It was 8 a.m. and raining, but Mr. Kaplan's outdoor classes run six days a week, year-round and without regard for weather. Mr. Kaplan, an American who has studied both the Chinese discipline of kung fu and its Japanese cousin, karate, for more than two decades, began leading classes in Columbus Park in 1994. Over the years, his class has hosted loyal martial arts practitioners and inexperienced aspirants alike, most either happening upon his sessions or learning of them through friends or neighborhood fliers. Until about a year ago, Mr. Kaplan charged students $100 a month for up to eight classes. But in response to the economic downturn and in the interest of encouraging regular participation, he instituted a pay-as-you-can policy. He also barters with students and has accepted artwork, an antique sword and a chicken dinner in exchange for long-term instruction. The classes run 60 to 90 minutes and typically take place on blacktop in the center of the park. But the rain on this recent morning displaced us and other regular exercise groups to the park's covered pavilion. Nine of us gathered in a circle and stretched, near dozens of older women who were engaged in traditional Chinese dance. Soon we began drills: front slap-kicks with arm rotations and punches, outside and inside kicks, and a series of warrior poses. Among these were bow-and-arrow and wide-leg horse stances - a sort of deep squat - with forward jabs. Mr. Kaplan, who works full time as a corporate fitness instructor and has performed martial arts in independent films, first demonstrated each pose in a crisp style that recalled Bruce Lee. Then he watched as we mimicked him (or tried to) in two single-file kick lines. Midway through the drills, he held up a red cushion as high as our heads and had each of us aim kicks at it. Mercifully, he lowered the height of my target after I'd struggled to reach it. He offered personal suggestions to each student, emphasizing technique and comfort over speed and extension. All the while, a Chinese man played a wooden flute above the traditional recording to which our neighbors were dancing with red and yellow paper fans. Onlookers came and went, several breaking from nearby chess games to study the moves of our mostly Western group. We concluded the class with leg-strengthening exercises - frog leaps and crouching duck walks - and another series of full-body stretches. Afterward, all but one student went for a traditional Chinese breakfast, a postclass routine. At Big Wong King on Mott Street, Tadashi Moriyama, a Japanese artist living in Brooklyn, ate his egg congee with gusto and related how he had created a drawing of Mr. Kaplan - one the instructor now uses in his marketing materials - in exchange for regular workouts. In addition to honing his martial arts skill, Mr. Moriyama said he had particularly enjoyed interacting with the local Chinese population. "It's a great cultural exchange," he said. Before I came to Chinatown just to eat. Now I come to exercise too. David Kaplan's classes are held in Columbus Park, Mulberry and Bayard Streets, Chinatown, at 7 a.m., Monday through Friday, and 8 a.m. on Saturday. Additional classes are held elsewhere. He takes donations. Details from brooklynshaolin@gmail.com.