Uphill lie in golf: shoulders parallel to the slope, ball toward the higher foot, one club more, aim right – supported by two studies with 12 golfers each.
In an uphill lie the ground rises toward the target. You set your shoulders parallel to the slope, place the ball closer to the higher foot, aim a bit to the right and often take one more club. Two studies with twelve golfers each support the basic principle: on a five-degree slope the ball flew left more often.
The honest answer to "How do I play uphill?" is: stand so that your body is perpendicular to the slope and expect the ball to pull left. In twelve elite players with a 6-iron on a 5-degree slope, pressure shifted on average by about 9 percent toward the lower foot. They set their feet wider and placed the ball closer to the higher foot [1]. Ball speed did not change, launch angle and spin did. Uphill the players tended to pull the ball to the left [1].
A second study with twelve mid-handicappers reached the same result. It found a weakness though: players tried to stand perpendicular to the slope at address but did not manage to hold that posture through the swing, unlike low-handicap players [2]. For you that means: a stable, calm swing matters.
On the number: five degrees is very gentle. Over ten meters the ground rises by just under a meter. Steeper slopes were not measured in these studies.
All descriptions are for right-handers; left-handers mirror them.
Do you stand securely? On wet grass or a very steep slope, safety matters more than distance. Then simply play out. You may not alter the slope: you may not press down grass or level the ground. Allowed is setting your feet firmly and digging in a bit in soft ground [3].
Milestone: you can say whether the slope is gentle, medium or steep, and whether you stand securely.
Tilt shoulders and hips so they follow the slope, the body stands perpendicular to the ground under your feet. The weight rests a bit more on the lower foot; in the study pressure shifted in that direction [1]. Mid-handicappers did not manage to hold this posture through the swing [2]. Hence: a calm swing.
Place the ball closer to the higher (front) foot. Both studies saw this in the players' practice [1][2]. The hands stay slightly ahead of the ball.
The slope pulls the ball left [1][2]. Aim a bit right of the target. The slope increases loft (experience-based; the abstracts of the studies do not name the direction): take one more club. Both are coaching values, not measured. Test with three balls.
Milestone: of ten balls at least seven land in a 20-meter corridor (a coaching benchmark).
Shorter, calm swing (three-quarter), keep balance. The finish ends with the weight down, no falling back. Do not swing against the slope, follow it.
On a slope the biggest danger is not the shot but the stance. If your foot slips, the swing can pull you off balance. Look for firm footing, wear shoes with grip and rather play out safely in wet conditions or on a steep slope. Check that nobody is in the line of play or next to you. Stop with pain in back, knee or ankle. This guide does not replace supervised training with a PGA pro or certified coach.
Practice the feeling beforehand on the range on a small ramp (e.g. a mat on a raised spot) with a gentle incline. That teaches you the posture without course pressure. Check your setup by phone video from the front: are the shoulders parallel to the slope? That is a practice trick, not a study.
Shoulders parallel to the slope, ball closer to the higher foot, aim a bit right and take one more club. In two studies on a 5-degree slope players tended to pull the ball left uphill [1][2]. A calm, shorter swing helps keep balance.
Rather left (right-handers). In both studies on a 5-degree slope, shots from uphill were more often hit left [1][2]. One reason is that the side spin changes [1]. Aim a bit right, therefore.
Usually yes, because the slope makes the ball higher and shorter. That is coaching practice; the studies only state that launch angle and spin change [1][2]. Test with three balls what difference you see on the course.
Closer to the higher (front) foot. In both studies golfers placed the ball in that direction on a slope [1][2]. The hands stay slightly ahead of the ball.
No. Rule 8.1 bans leveling the ground or pressing down grass when it improves conditions. Allowed is setting your feet firmly and digging in a bit in soft ground [3].
Downhill Lie in Golf: How to Play the Ball on a Downslope