The term five-and-half appears in carom instruction and research. A name alone does not identify every mark, correction or stroke assumption. Start with the complete chart you are using.
What the reference supports
Park and Park’s 2022 assistive-system paper uses a five-and-half diagram in its path-generation method. Alciatore’s Corner-5 explanation and technical proof show related but separately labelled departure, aim and arrival scales. Neither establishes that Korean players simply divide every diamond by five or that professionals share one setting.
Units are not precision
As arithmetic on matching scales, departure 5.5 minus aim 3 gives arrival 2.5. Multiplying all scales by ten gives 55−30=25. The line has not improved because the labels became larger or decimal. Reading and executing remain separate sources of error. Do not repair an unsupported negative aim by wrapping around a perimeter scale.
Read along the aiming line
Project the proposed aiming line backwards through the cue-ball centre to read departure. Changing aim can change this projection. Use first-cushion and arrival values from the same chart, with appropriate spin and pace assumptions. For a ball-first route, evaluate the departure after the first collision.
Compare a reference
Save coordinates and predict the third-cushion arrival. Repeat with fixed pace and spin, then change one input and record the difference. Keep model results separate from real-table observations. This arithmetic is not a tested scoring route or a millimetre-accuracy promise.
Practise with available controls
Use the position library and replay to inspect contacts, and the linked Corner-5 lesson for a worked scale example. This lesson does not promise a separate Korean-mode setting. A useful comparison begins with the positions and controls actually available.