The Day Basketball Broke: How a Single Line Changed the NBA Forever

The roar in TD Garden was so loud it felt like the old brick building was shaking. With 7.8 seconds left on the clock, Stephen Curry caught the inbounds pass at halfcourt, dribbled twice to his left to create a sliver of space from Jayson Tatum’s outstretched arm, and launched the ball from 35 feet out—four feet behind the three-point line. The crowd held its breath for two full seconds as the ball hung in the rafters, spinning perfectly on its axis, before it swished through the net without touching the rim. The buzzer blared. The scoreboard flashed 110-107. And the NBA’s all-time three-point scoring record, held by Ray Allen for 11 years at 2,973 makes, was now Curry’s.

For the 19,156 fans in attendance, most of them Celtics season ticket holders who’d spent decades hating Curry’s guts for breaking their hearts in the 2022 Finals six months prior, the reaction was shockingly unanimous: they stood. They cheered. Some even cried. Even Celtics head coach Joe Mazzulla, who’d spent the entire game instructing his team to force Curry to his left and “make him take a tough shot,” clapped from the sideline. Curry, meanwhile, ran with his mouth agape, slapping palms with teammates before burying his face in his jersey, sobbing. His father, former NBA sharpshooter Dell Curry, was crying in the stands too, holding up a sign that read “#1 Son” as confetti rained down. The moment wasn’t just a buzzer-beater. It was the final, undeniable proof that the three-point shot, once written off as a gimmick no serious player would ever rely on, had become the most important play in basketball history.

<!-- 印刷版侧边栏：三分线的诞生 --> <span style="float: right; width: 30%; margin: 0 0 1em 1em; padding: 1em; border: 1px solid #ccc; background: #f9f9f9;"> <strong>📖 印刷版侧边栏：三分线的ABA起源</strong><br> 绝大多数球迷不知道，NBA的三分线根本不是联盟原创的。1976年，挣扎求存的美国篮球协会（ABA）和NBA合并，ABA为了吸引年轻球迷，搞出了三个划时代的“花活”：三分线、扣篮大赛、红白蓝三色篮球。合并后，NBA总裁拉里·奥布莱恩怕流失ABA的老球迷，直接照搬了这三个设定，三分线就这样在1979-80赛季正式进入NBA——最初的目的根本不是优化战术，纯粹是营销噱头。 </span> <!-- 电子版超链接：库里破纪录绝杀回放 --> [📱 电子版点击观看库里破纪录绝杀回放](https://www.nba.com/video/curry-2974th-three-buzzer-beater-celtics-2022) <!-- Markdown标签：#three-point-origin #nba-history #stephen-curry -->

To understand why that shot mattered so much, you have to rewind 43 years, to a time when shooting a three-pointer was considered a sign of desperation, not skill. On October 12, 1979, the Boston Celtics hosted the Houston Rockets in the first regular-season game with the new 22-foot three-point line. Celtics backup guard Chris Ford took the first ever NBA three-pointer in the first quarter, a contested 22-foot jumper that swished through the net. He didn’t even celebrate. “I didn’t even know it was a three,” Ford laughed in a post-game interview. “Coach [Bill Fitch] never mentioned it in practice. I just shot a jump shot, and when my teammates ran over to hug me, I thought I’d done something wrong.” The crowd cheered, but the Celtics’ coaching staff was less than impressed: Fitch benched Ford for the rest of the game for “taking a low-percentage shot.”

That reaction summed up the NBA’s view of the three-pointer for the next 30 years. Coaches called it a “garbage shot,” something you only took when you were down by 10 with 10 seconds left, because the math didn’t add up. Let’s do the math yourself, using the same logic NBA coaches used in the 1980s: <!-- LaTeX公式：每次出手得分效率 --> $$每次出手得分效率 = 三分命中率 \times 3$$ In the 1980-81 season, the NBA’s league-wide three-point shooting percentage was just 29.8%. That means the average three-point attempt was worth: $$29.8\% \times 3 = 0.894 \text{ 分每次出手}$$ Compare that to the two-point field goal percentage that same season: 49.2%. The average two-point attempt was worth: $$49.2\% \times 2 = 0.984 \text{ 分每次出手}$$ Why would you ever take a shot that gave you 0.09 fewer points per attempt, on average? That’s the exact question every NBA coach asked their players for three decades. The three-pointer was a novelty, a marketing gimmick to sell tickets, not a legitimate part of the game.

The numbers didn’t get any better in the 1990s, the era of Michael Jordan and the Chicago Bulls’ six championships. Jordan, widely considered the greatest basketball player of all time, took just 1.7 three-point attempts per game over his career, and shot a paltry 32.7% from deep. In the 1997 NBA Finals, he hit just 1 of 6 three-point attempts in Game 6 to clinch the title against the Utah Jazz—his famous “last shot” was a mid-range jumper over Bryon Russell, not a three. The league-wide average three-point attempt total per game that season was just 13.2, less than half of what it is today. The three-pointer was still an afterthought, a last-resort option for players who couldn’t get a good look at the rim inside.

The first crack in the three-pointer’s “gimmick” reputation appeared in 1997, when the NBA adjusted the three-point line from 22 feet everywhere to the current standard: 23 feet 9 inches (7.24 meters) at the top of the arc, and 22 feet (6.7 meters) in the corners. The league said the change was to align with international basketball rules, but it also made the shot harder: the extra 20 inches in the corners and 11 inches at the top of the arc meant even the best shooters had to adjust. Reggie Miller, who held the all-time three-point record at 2,560 makes at the time, complained publicly that the change would “kill the three-point game.” He was wrong, but only because no one could have predicted what would happen next.

For the next 17 years, the three-pointer remained a niche shot, used mostly by designated “sharpshooters” who came off the bench to space the floor. The league-wide three-point attempt average crept up slowly, from 13.2 per game in 1997 to 18.1 per game in 2010. The math still didn’t favor the three: even with the line moved back, the league-wide three-point percentage had only climbed to 35.8% by 2010, which meant the average three-point attempt was worth 1.074 points per shot—just barely better than the average two-point attempt (0.98 points per shot). Coaches still saw it as a low-percentage gamble, not a core part of their offense.

<!-- 印刷版侧边栏：规则改动的蝴蝶效应 --> <span style="float: right; width: 30%; margin: 0 0 1em 1em; padding: 1em; border: 1px solid #ccc; background: #f9f9f9;"> <strong>📖 印刷版侧边栏：2014年规则改动的蝴蝶效应</strong><br> 2014年NBA出台了两条看似不起眼的规则：1. 禁止“handcheck”（防守球员不得用手触碰进攻球员腰部或以下部位阻碍其移动）；2. 严格执行防守三秒（防守球员不得在三秒区内停留超过3秒，不防守对位球员）。这两条规则看似和三分球无关，实则直接解放了外线球员的出手空间：过去防守球员可以贴身用手顶住外线射手，现在只能靠脚步和手臂干扰，出手速度快的射手几乎不可能被封盖。 </span>

Everything changed in 2014, when the NBA cracked down on “handchecking” and defensive three-second violations. For the first time, defenders couldn’t put their hands on the waists of perimeter players to slow them down, and big men couldn’t camp in the paint for entire possessions. Overnight, the outside became wide open. The Golden State Warriors, a small-market team that had just drafted a skinny, 6-foot-3 point guard from Davidson College named Stephen Curry, were the first to capitalize.

Curry was not a typical NBA prospect. He was too small to guard NBA shooting guards, too slow to beat defenders off the dribble, and he spent his entire college career shooting threes from 30 feet out, a distance most coaches told their players to never even try in a game. The Warriors’ front office, however, had crunched the data: Curry’s three-point release time was 0.4 seconds, half the league average of 0.8 seconds. That meant even if a defender closed out perfectly, Curry would get the shot off before the defender could reach him. He also had a career 43.8% three-point shooting percentage in college, which meant his three-point attempts were worth $43.8\% \times 3 = 1.314$ points per shot—already better than the average two-point attempt.

The Warriors didn’t just let Curry shoot threes. They built their entire offense around him. They designed pick-and-rolls to force defenses to switch onto Curry, leaving him one-on-one with a slower big man who couldn’t keep up