The Blank Scouting Sheet in Binh Duong: The Undug Data Layer of Vietnamese Youth Tennis

In July, on the stands of a tennis court at a sports training centre in Binh Duong, I sat with a notebook and a stopwatch. The under-16 quarter-final had ended after two hours and seventeen minutes. A coach walked past and handed me the organiser's official scouting sheet: fourteen boxes, from first-serve percentage to first-serve points won, break-point conversion, and tie-break points won. Every one of them was empty. The only line written in blue ink, in slanted handwriting, read: "Has potential."

I still keep that sheet. It sits in the second drawer of my desk, next to other sheets that are nearly as blank, collected over six seasons of junior tennis.

People call that a failure of the academy. I call it a layer of earth nobody has dug up.

Vietnamese youth tennis runs on a narrow tournament system, tiered by age group: under-12, under-14, under-16, under-18, organised by regional clusters. These events crown champions, but they produce almost no data. Results are recorded as set and game scores. Nobody writes down how many points a fifteen-year-old won on his second serve, or how he handled a 30-40 point while his opponent was serving.

Behind the domestic courts sits a harsher system. The ITF World Tennis Tour Juniors grades events from J30, J60, J100, J200, J300 up to J500, each tier tied to a ranking-point scale. Vietnam hosts very few events inside that system. To collect points, a junior has to travel to Thailand, Malaysia, Indonesia, the Philippines, Chinese Taipei or Japan. A five-day trip, including flights, hotel, entry fee and one accompanying coach, usually swallows twenty to forty million dong. That number decides the schedule, and the schedule decides the ranking.

There is a paradox here. The ITF Junior ranking is a public metric everyone can see, but it measures the travel budget almost as much as it measures level. The metrics that genuinely reflect level sit in coaches' hands, written by hand, and most of them are left blank.

Inside the dust of time, I dug out a scouting sheet that still has a pulse.

The first layer: the serve. This is the most neglected area. A junior needs at least four metrics for anyone to understand how he serves: first-serve percentage, first-serve points won, second-serve points won, and double faults per service game. Without all four, a coach is left with one sentence: "the serve isn't stable yet."

I once tracked a fifteen-year-old across seven matches at a junior event in southern Vietnam. He landed only forty-eight per cent of first serves, and was therefore filed under "weak server." But when I counted point by point, his first-serve points won reached seventy-one per cent, and his second-serve points won was fifty-two per cent. His serve was not weak. It was strong but unstable. Those are two entirely different problems requiring two entirely different fixes: one is more work on the toss and the rhythm of the release, the other is rebuilding the whole motion.

That fifty-two per cent figure says something more. At this age, second serves are usually attacked head-on. A player who holds more than half his second-serve points already owns a deliberate second-serve pattern, rather than a push to get the ball in play. That kind of detail never appears on a scoreboard.

The second layer: the return and break points. The percentage of points won on an opponent's serve, and break-point conversion, are the two metrics that directly reflect the ability to convert chances. In domestic junior events, a set can contain five or six break points, yet nobody records how many a player converted. The result is that two players can arrive at the same 6-4 scoreline with completely different values: one converted two of two chances, the other two of nine.

The third layer: the line between aggression and recklessness. The ratio of winners to unforced errors is the most useful diagnostic tool between the ages of fourteen and eighteen, because it separates a proactive player from a careless one. Two players can both lose 4-6 and both make twenty-eight errors, but one has eighteen winners and the other only six. The first is building a game. The second is waiting for the opponent to miss.

The fourth layer: score-state data. Performance at 4-4, at 5-5, in tie-breaks, at deuce. This is the data zone that shows how a junior handles pressure, and it is also the most neglected, because it requires an observer to sit through the whole match, marking every point, rather than just noting the final score. Based on my experience watching twenty-two matches live at national junior events, the gap between winners and losers at under-16 level usually does not lie in total points won, but in four to six decisive points per set.

The fifth layer: points structure and defence windows. ITF Junior points are valid for twelve months, and all junior points vanish when a player turns nineteen. That means every junior has a golden window of roughly three years to accumulate enough ranking capital before entering the professional system. Very few families and very few coaches track this window as a strategic variable. They pick events by feel, by free time, or by whether someone can travel with them.

The sixth layer: competitive load. Matches per month, different surfaces within one cycle, flight hours, time-zone changes, injury history in the shoulder and wrist. Vietnamese tennis is almost entirely hard court. When players go abroad to clay or carpet events, the switch costs more than technique: sliding, stopping, changing direction, and the entire muscle chain through the hip, thigh and ankle has to work differently.

The seventh layer: management records. Which coach travels, who manages the schedule, who negotiates sponsorship, the terms of an academy scholarship, the length of a contract. This is the information that decides a junior's career, and it barely exists in written form.

Every academy is a site. Every generation of players is a cultural layer. I am only the one who writes it down.

Looking at how Ly Hoang Nam went from the junior courts of Tay Ninh to the 2026 junior Wimbledon boys' doubles title alongside Sumit Nagal, and then into the ATP top 250, people usually tell a story about talent. But the more interesting thing is structural: he was a case with enough resources and enough international schedule for his golden window not to close. Other players have the same hand speed but not the same flight schedule. Nguyen Thuy Linh, the Vietnamese woman who has held the highest WTA ranking in the country for years, is also a curve fed by a continuous volume of international events, not by a single domestic tournament.

Here is the truth at junior level: a player ranked three hundred in ITF Juniors may have played twenty events in a year, while a player ranked six hundred played only six. That three-hundred-place gap may come from level, but it may also come from a wallet.

The point is that the solution is not to build a data ivory tower. I have seen thirty-column tracking sheets created and then abandoned after two weeks, because nobody had time to enter the data and nobody knew what to do with the output. More data does not automatically produce better decisions. What is missing is not volume but the feedback loop: the numbers have to return to the training court, become a specific, measurable exercise, and be checked again four weeks later.

There is another trap. Once data collection begins, people drift towards early developers: taller, stronger, harder-hitting. But at under-14 level, physical metrics carry far too much weight compared with technical ones. A small player with a good second-serve points-won rate and high break-point conversion may well overtake the very players beating him at fourteen. Data is only honest when the reader knows what it is measuring.

Finally, there is a point easily missed in the very idea of using numbers to judge people. Most of the data in this article concerns children who are not old enough to decide their own careers. How a coach reads those numbers and communicates them to a fifteen-year-old boy matters no less than the numbers themselves. A metric said at the right moment can open up a good training session. Said at the wrong moment, it closes a belief.

I do not write reports. I excavate the memories of players who have never been told.

Every blank box on a scouting sheet is a question nobody has asked yet. A low first-serve percentage combined with a high first-serve points-won rate tells you what about how he should train over the next three months? This player converted two of nine break points at 5-5 in the third set, so which part of the return should be dissected first? And if junior points disappear when a player turns nineteen, who is watching that countdown clock?

The data of today's junior generation is the bas-relief of tomorrow's tennis history. The next brick is still in the ground, and the next sheet is still blank.