What size steel for a yanagiba?

A yanagiba is long and narrow. Its height at the heel sets the width of the bar, and its length sets how much bar you buy. The preset is a 10 1/2 in blade (about 270 mm), 1.3 in tall at the heel, with a 5/32 in (0.156 in, about 4 mm) spine and a 5 in hidden tang for a wa handle. Add 1/8 in for clean-up and you need 1.425 in, which rounds up to 1 1/2 in. That makes it 1 1/2 × 5/32 in flat bar, forged or ground. A yanagiba up to 1 3/8 in tall still fits 1 1/2 in bar. Any taller and the calculator moves you up to 2 in.

The matching KraftyDesign blank (the "Draw this blank" link) is long and narrow. The edge runs almost straight and only sweeps up near the point, which sits close to the spine. The handle hangs from the spine line. KraftyDesign starts Japanese patterns at 3/32 in, but real yanagibas are thicker than that at the spine, so the preset uses 5/32 in.

The preset's spine comes from shop knives. Spec tables from five knife shops list six 270 mm yanagibas at 3.7 to 5 mm (about 0.15 to 0.20 in) at the spine, and 5/32 in (3.97 mm) sits inside that range. Five of them give a height, from 33 to 39 mm (about 1.3 to 1.5 in), so 1.3 in is at the low end. Some makers go thinner. In a BladeForums thread, one poster finished a 266 mm AEB-L yanagi with a 0.125 in spine and no taper. For a spine that thin, set 1/8 in. At the preset's 1.3 in height the bar becomes 1 1/2 × 1/8 in.

The calculator starts on 1084. On stock removal, 1095, W2, 52100, AEB-L and MagnaCut give the same 1 1/2 × 5/32 in bar with no flags. 5160 gets one: 5/32 in is not a size 5160 is commonly listed in. Long single-bevel blades like this one can move. In a BladeForums thread on a yanagi for a friend, one poster says these blades need straightening out of the quench and can also warp during grinding and polishing. Another poster there would pick 52100 over AEB-L for less warping on a long blade, and expects the blade to arch in heat treat if the bevel is ground first.

The calculator starts on stock removal for this one. Stock removal takes the whole 15 1/2 in profile plus clean-up: 15 3/4 in of bar per blade. That is about 17 oz of bar (just over 1 lb) for a blade that finishes around 8 oz. A 12 in bar is too short. The 18 and 24 in bars give one blade each, a 36 in bar gives two and a 48 in bar gives three at the lowest cost per blade. The shops list their 270 mm yanagibas at 189 to 205 g (about 7 oz) with the handle on, so the calculator's steel-only estimate may run heavy. Weigh your first one and adjust the fill factors under Calibration if it comes out lighter.

Forging the bevels and the point stretches the blade, a 1.98:1 draw by the calculator's count, so about 8 in of the same bar (about 9 oz) is enough. The blade finishes near 6 oz. A 12 in bar gives one, 18 and 24 in give two each, 36 in gives four and 48 in gives five, with 18 and 36 in tied for the lowest cost per blade. If you start thicker and forge down, set "Forged thickness" to "One size up". That starts you at 1 1/2 × 3/16 in, and it only applies in forged mode. The calculator won't forge AEB-L, CPM-154, 14C28N, MagnaCut or A2. Pick any of them and it works out the bar as stock removal, even with Forged selected.

What a yanagiba is for

A yanagiba is a Japanese knife for slicing raw fish. Korin, a Japanese knife shop in New York, says it is used to slice boneless fish fillets into sashimi and toppings for sushi, and that the long, thin blade is designed to cut each slice in one drawing stroke. Wikipedia explains the shape the same way. The long blade lets you cut a block of fish in a single stroke, and the blade is so thin behind the edge that the weight of the knife does most of the cutting. Unlike most Western knives, it is pulled through the cut rather than pushed. A Japanese dictionary of kitchen tools published by Kodansha gives the reason for the length. To leave a smooth cut face, the slice is pulled through without sawing back and forth, so the blade is long and narrow. The same dictionary describes the yanagiba as the sashimi knife with a pointed tip. Wikipedia gives 25 to 35 cm (about 10 to 14 in) for sashimi knives in general. Sakai Ichimonji Mitsuhide, a knife maker and shop in Osaka, says 21 to 24 cm blades are popular at home and 27 to 30 cm with professional chefs. The preset's 10 1/2 in is just under 27 cm. Knifewear, a Canadian knife shop, adds that a yanagiba can also carve roast beef and prime rib.

Like other traditional sashimi knives, it is single bevel. Wikipedia says a right-handed yanagiba has its bevel on the right side and is concave on the left. That hollow is the urasuki, and BladeStock's deba page covers how makers grind one. Wikipedia says the best single-bevel blades have one, and that it allows thinner slices but takes more skill to use. A left-hander needs a mirror-image knife. Three of the six shop knives above are white (shirogami) or blue (aogami) steel, and neither is on BladeStock's list. One BladeForums post shows a W2 yanagi with a hamon, 310 mm long with a 4.5 mm spine. Korin says the yanagiba originated in the Kansai (Osaka) region. The Kodansha dictionary says it was used mainly in Kansai, while Kanto (around Tokyo) used the takohiki. That knife has its spine parallel to the edge and the same width from heel to tip, so the blade is a long rectangle. The dictionary adds that the yanagiba is now the more common of the two. The fuguhiki is a third sashimi knife. Ichimonji says it is thinner and lighter than the yanagiba and takohiki, and suits fugu (pufferfish), whose quite hard flesh has to be sliced very thin. The sashimi knife itself goes back at least three centuries. The Nihon Kokugo Daijiten, a large Japanese dictionary, gives its earliest written use of the word sashimi bōchō (sashimi knife) as a line in a puppet play by Chikamatsu Monzaemon from the early 1700s.

The stories and name readings in this paragraph are unconfirmed or conflict with each other, so take them as lore, not history. A 2013 post on the blog of Japanese Knife Imports, a knife shop in Beverly Hills, says Kanto cooks used to sit while cutting, with their boards higher relative to their bodies. That called for flatter knives without a sharp tip, like the takohiki. Kansai cooks stood, the post says, which made the yanagiba's curved profile more useful. The names are just as loose. Wikipedia says yanagi comes from the long, pliant willow branch, while Knifewear translates the name as willow's leaf. Hocho-Knife, a knife seller that lists addresses in Florida and Japan, says the yanagiba is also called shōbu in western Japan. Shōbu is a Japanese word for the sweet flag and, informally, the Japanese iris, and Ichimonji's English site says the yanagiba most resembles the iris. Wikipedia says the takohiki is usually used on octopus and squid. Hocho-Knife says it is not for octopus but for sashimi.

Stock for a yanagiba

In a BladeForums thread on yanagiba geometry, one poster likes a 240 to 250 mm blade about 30 mm tall and 3 to 4 mm (0.125 to 0.155 in) thick at the handle, with a 25 to 30% distal taper. In the thread on a yanagi for a friend, the maker who started it bought 1 1/4 × 1/8 in 52100 for a blade about 10 1/2 in from heel to tip. The 266 mm AEB-L yanagi mentioned above was 37 mm (1.46 in) tall, which the calculator would put on 2 in bar.

Widths assume blade height + 1/8 in rounded up to stock; thickness is the finished spine rounded up. Change the inputs above for your own pattern.

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