3/8" Japanese Ratchets Compared: 8 KTC & Ko-ken Models by Teeth, Length, Weight & Head

If you are choosing a 3/8" drive ratchet from a Japanese maker, the two names you will see most often are KTC and Ko-ken. This guide compares the eight 3/8" ratchet handles we carry from those two brands, using numbers from manufacturer catalogs wherever they are published. Where we could not confirm a figure from a reliable source, the table says Not confirmed instead of guessing.

The comparison table

All eight models use a 3/8" (9.5 mm) square drive, so they fit standard 3/8" sockets. Tap a model name to see its current price and details. Need more leverage for bigger bolts? See our 1/2" ratchet comparison.

KTC BR390L Long ratchet handle (90-tooth gear), 3/8" (9.5 mm) Drive KTC BR390FL Flex Long Ratchet Handle (90-tooth gear), 3/8" (9.5 mm) Drive

* KTC lists two thickness figures for the BRSW3L swivel head. ** Head width reported for the 3776 series (3776J); the 3776N uses the same head with a metal handle. See Sources below.

How to read these numbers

Gear teeth and swing arc

The swing arc is how far you must move the handle before the ratchet picks up the next tooth. A smaller number lets you work where the handle can only move a little. KTC's own catalog compares its 90-tooth BR390 series (4°) with its earlier 36-tooth standard ratchet (10°). Ko-ken's 24-tooth ratchets have fewer teeth, but Ko-ken uses a two-pawl design, so tooth count alone does not tell you the swing arc. We have not found a published swing arc for the Ko-ken models, so we leave it unconfirmed.

Back-drag

Back-drag is the resistance you feel when the ratchet clicks backward. When it is too high, a loose bolt turns back with the socket instead of staying put. Ko-ken has long made low back-drag a design priority, and its engineers have explained that keeping it low was a key difficulty when Z-EAL moved from 36 to 72 teeth. No maker publishes a comparable back-drag figure, so it is not in the table.

Head type

A flex head (BR390FL, 3726Z, 3726Z-280) tilts the head to reach around obstacles. A round swivel head (BRSW3L, 3776N) turns far enough to line the handle up with the socket, so you can spin the fastener quickly like a screwdriver, then swing the handle back to tighten.

Model notes

KTC BR390L — long handle, 90 teeth

KTC's long version of its BR390 ratchet: 275 mm, 350 g, 4° swing arc. KTC sells a head repair kit (BR390-K) that fits the whole BR390 series.

View KTC BR390L

KTC BR390FL — long handle with flex head

The same 90-tooth head and 275 mm length as the BR390L, plus a head that pivots through 180°. It weighs 20 g more (370 g). KTC notes that pushing too hard on the flex joint can make the work unstable.

View KTC BR390FL

KTC BRSW3L — long swivel, 72 teeth

The longest model here at 300 mm. KTC describes the head as one of the smallest in its class for a 3/8" ratchet. The handle turns 180° or more around the head, so it can be used like a ratchet screwdriver. KTC warns that the long handle makes over-tightening easy.

View KTC BRSW3L

Ko-ken 3753N — 24-tooth everyday ratchet

A 200 mm ratchet with an all-metal handle and a 30.5 mm head width, as reported by Young Machine. A good first Japanese ratchet if you work in open spaces more than tight ones.

View Ko-ken 3753N

Ko-ken Z-EAL 3725Z-280 — long, 72 teeth

The long (280 mm) version of Ko-ken's standard Z-EAL ratchet. Ko-ken's 3/8" Z-EAL ratchets now use a 72-tooth gear, and Ko-ken kept the same part numbers when it made the change.

View Ko-ken 3725Z-280

Ko-ken Z-EAL 3726Z — flex head, standard length

The standard-length Z-EAL flex-head ratchet, shorter than the 3726Z-280. A good fit for engine bays and machinery where a long handle has no room to swing.

View Ko-ken 3726Z

Ko-ken Z-EAL 3726Z-280 — long flex head

The 280 mm version of the 3726Z, for extra leverage while keeping the flex head. It is the closest Ko-ken match to KTC's BR390FL.

View Ko-ken 3726Z-280

Ko-ken 3776N — round swivel head, 45 teeth

The pivot sits in line with the drive, so the handle can be used like a screwdriver for fast spinning. You choose the direction with a ring around the round head. The head is wider than Ko-ken's fixed-head ratchets (44 mm reported for the 3776 series).

View Ko-ken 3776N

Which one should you buy?

If your main problem is no room to swing the handle, start with the KTC BR390L. It has the smallest published swing arc here. Choose the BR390FL if you also need to angle around obstacles.

If you run long bolts in and out, a round swivel head saves time: the KTC BRSW3L if you want the published specs and the longest reach, or the Ko-ken 3776N if you prefer Ko-ken.

If you value a light, smooth click on small fasteners, look at Ko-ken's Z-EAL models: the 3726Z for tight spaces, or the 3725Z-280 / 3726Z-280 for reach.

If you want one simple, dependable everyday ratchet, the Ko-ken 3753N is the straightforward choice.

Still deciding between the two brands? See KTC vs Ko-ken: which Japanese socket brand should you buy?

FAQ

Related guides

• 1/2" Japanese ratchets compared: 8 KTC and Ko-ken models
• KTC vs Ko-ken: which Japanese socket brand?
• Japanese ratchet tools for tight spaces
• NEPROS NBR390A: KTC's premium 90-tooth 3/8" ratchet
• 6 Japanese socket sets compared

Sources

• KTC product flyer No.75-10: BR390 series (teeth, swing arc, length, weight, head dimensions for BR390L and BR390FL)
• KTC product flyer No.72-13: BRSW3 / BRSW3L (teeth, swing arc, length, weight, head dimensions)
• MISUMI product page for KTC BRSW3L (cross-check of weight and tooth count)
• Young Machine (2021): Ko-ken Z-EAL 72-tooth ratchet development
• Young Machine (2022): Ko-ken 3753N head width and length
• Young Machine (2023): Ko-ken Z-EAL 3/8" lineup
• Young Machine (2024): Ko-ken swivel ratchets incl. 3776 series
• Freer Tool (US Ko-ken distributor): 3753N and 3776N (teeth and length)

Specifications may change. Always confirm current specifications with the manufacturer for safety-critical work. Last reviewed: October 2026.