Editing Fishing reel (section)

=== Line guide mechanisms ===
Line guides are unique to multiplier reels, as more evenly wound lines on the spool would allow the reel to function more smoothly and prevent unwanted "overspill" of line at either end of the spool. The vast majority of line guides are a simple ring or short cylinder with a {{cvt|2|-|3|mm|2}} internal diameter, which slides horizontally along a spiral-groove [[shaft (mechanical engineering)|shaft]]. The side-to-side motion of the line guide continuously pushes and realigns the line onto different section of the spool, thus allowing a more even distribution of winding.

While line guides are crucial to reel operation during retrieval, during casting it becomes more of a hindrance because the line will have to go through its narrow internal channel to leave the reel. This creates additional [[drag (force)|drag]] from [[friction]] (especially when the line kinks against the back rim of the guide) or when loose line loops whips against the line guide. This exacerbates backlashing as the narrow line guide channel often limits how fast the line can leave the reel, and is particularly a problem when the line guide stops near the side of the reel when the reel gears are disengaged during casting. There are design modifications on line guides aimed to minimize resistance against line release, most of which involve having a [[conical]] or [[funnel]]-shaped line guide that reduce the kinking angle between the line and the guide frame, which only partially resolves the drag issue. Another less-successful modification involves having an open-and-shut "gate" as a line guide, which unfortunately can catch and trap the line between the gaps of the shutter.

In 2011, the famous Japanese fishing tackle brand [[Globeride|Daiwa]] introduced its famous TWS (T-Wing System) design, which have a T-shaped/inverted trianguloid line guide that has a broad top section that presents a much wider channel for line exit, while during retrieval the top bar tilts back and down to push the line into the much narrower bottom section. The TWS has become a celebrated success for Daiwa, and remained a patented trademark that was largely unchallenged for years.

Another notable 21st century line guide design, patented by the [[Shenzhen]]/New York City-based Chinese-American brand KastKing in 2023, is named the "Axis Eye" or "[[weeping willow|willowleaf]] guide". It has a [[silicon nitride]]-coated, [[rounded rectangle]] frame with a slightly [[serpentine shape]]d top profile, which can horizontally rotate 90° to alternate between a wide and a narrow [[cross section (geometry)|cross-section]]al width. During casting, the line guide is rotated to a transverse orientation, which presents a {{cvt|17.6|mm|1}}-wide line channel, allowing the line to exit with minimal drag; during retrieval, the line guide is rotated to a longitudinal orientation, which narrows the line channel down to less than 3&nbsp;mm.