The 1:2 triangle: start by reading the reference line
Read the 1:2 triangle from a back-around and side-around lesson, and tell the reference line apart from the actual stroke.
For beginners · about 20 min of practice · Based on a video by 방수좋아 당구TV
One thing to remember today
1:2 is a ratio of lengths. It is not a thickness or a number of tips.
Written and edited by TTBoys · How we write and check sources · Report an error
The cue ball is the ball you strike; the first object ball is the ball you hit first. Bangsujoa's 1:2 reference lesson reads the path with a triangle. First compare the lengths of the two sides that meet at a right angle, then connect them to the actual ball layout. Don't think of the reference triangle's hypotenuse as the actual path the ball follows all the way.
1. Start with the original scene
If playback is blocked or you want to see the scene again, watch from 2:00 on YouTube ↗
The scene buttons jump to the times we checked. Keep watching for the full explanation and the actual shot.
2. Sum it up in a diagram and check the conditions
- Ratio
- A reference shape with a short side of 1 and a long side of 2 meeting at a right angle. The diagram below explains only this ratio; it does not reproduce the source's ball coordinates or aim points.
- Layout
- First check the three corners of the triangle and the ball positions on the 6:00 screen. If the distances between the cue ball, the first object ball and the cushion change, you need to read the stroke conditions again.
- Spin
- At 4:00 there is an instruction to give plenty of spin. Don't turn this into a rule that everyone should use the same maximum number of tips. Look at the left-right and up-down tip position and the motion in that example together.
- Scope
- Keep the back-around and side-around examples apart. Reading the same triangle does not automatically decide thickness and speed as well.
3. Follow the steps
Find the two sides at a right angle
Watch the explanation from 2:00 and pause at 6:00. Point at the triangle's short side and long side, and make sure you haven't confused them with the hypotenuse.
Mark the three balls separately
The corners of the drawing and the ball centers are different marks. Name the cue ball, the first object ball and the second object ball in order, then find where the actual shot starts.
Read the stroke conditions as one set
Don't shoot from the line alone; check the thickness, tip position and speed in the stroke scene that follows. If you're not used to it, set up one layout with a coach and repeat it.
Compare from the first cushion
Repeat the same layout 5 times and record where the ball entered the first cushion. Think separately about whether you misread the reference line or your stroke changed.
If it isn't working, start here
Reading 1:2 as half-ball thickness or 2 tips
Here it is the ratio of the triangle's side lengths. Check the actual thickness and spin separately in that example.
Aiming the triangle's hypotenuse straight at the object ball's center
The line for reading the reference and the line for hitting the ball do different jobs. Check the cue ball's direction after the object ball contact too.
A drill suggested by TTBoys
4. Reading the triangle 5 times + one layout 5 shots
Reps 1–5: Pause the source and explain the triangle and the positions of the three balls out loud.
Reps 6–10: Choose one layout from the source and repeat it 5 shots with the same stroke conditions.
This introductory drill was put together by TTBoys. Don't combine reading and stroke results into a scoring rate or system accuracy.
For the first 5, it's done when you can tell the short side, long side and hypotenuse apart; for the last 5 shots, it's done when the ball enters the first-cushion section you set in advance.
Tap a number to cycle: not recorded → hit → needs work.
0/10 recorded · goal hit 0 times
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Related reading
Sources and what was checked
1대2기준을 기억하면 당구가 쉬워집니다! | 뒤돌리기,옆돌리기 전부가능 | 방수좋아 당구레슨 12탄
방수좋아 당구TV · Published 2025-11-25 · Checked 2026-10-10
Why this video: #3 by popularity on the 방수좋아 당구TV Videos tab · 1,791,707 views (checked 2026-10-03). This is not an overall ranking including Shorts and live streams, and views and order can change.
Third in the official channel's Videos tab sorted by popularity. We checked the description and the triangle, spin and layout screens at 2:00, 3:00, 4:00 and 6:00. This is a drill in reading the reference, not a rulebook rebuilding the full correction method.
We checked the video description and the selected scenes. We did not verify the full transcript or measure anything on a real table. The steps, diagrams and 10-shot drill are TTBoys' editing and do not imply review or partnership by the creator.