What size steel for a santoku?

A santoku is a short kitchen knife with a tall blade, and the height is what sets the bar. The preset is a 6 3/4 in blade (about 171 mm), 1.85 in tall at the heel, with a 3/32 in (0.094 in) spine and a 5 in full tang. Add 1/8 in for clean-up and the height comes to 1.975 in, so it comes out of 2 in bar: 2 × 3/32 in flat bar. The matching KraftyDesign blank (the "Draw this blank" link) has a flat edge with only a slight curve, and the spine rolls down to meet it at the point. That rounded nose is the sheep's foot tip. Thin matters on this knife. America's Test Kitchen (ATK) tested santokus and found its top-rated knives were all about 2 mm (about 0.08 in) or thinner at the spine, against up to 2.6 mm for lower-rated ones. So 3/32 in bar leaves a little to grind off. The calculator starts on 1084, and AEB-L, MagnaCut and 52100 give the same 2 × 3/32 in bar. 14C28N is sold in metric thicknesses, so the calculator flags 3/32 in as uncommon for it. Check what your supplier stocks.

The calculator starts on stock removal for this one, because a santoku is thin and flat. Stock removal takes the whole 11 3/4 in profile plus clean-up: 12 in of bar per blade, about 10 oz of bar for a blade that finishes around 7 oz. A 12 in bar gives none once the saw cut is counted, a 36 in bar gives two, and a 48 in bar gives three at the lowest cost per blade. Forged, the blade stretches as you draw out the bevels, so about 10 1/4 in of the same bar (about 9 oz) is enough, and the blade finishes near 6 oz. A 24 in bar gives two, 36 in gives three and 48 in gives four, all at the same cost per blade. Some smiths who forge kitchen knives start thicker and forge down. In a BladeForums thread on chef's knife forging thickness, one forges from 1/4 × 1 1/4 in bar and pulls it out to 2 in at the heel. Another says 0.10 to 0.12 in is a good place to stop forging and start grinding. If you start thicker, set "Forged thickness" to "One size up", which starts you at 2 × 1/8 in. If you forge the width out of narrow bar, go by the steel weight the calculator gives rather than the bar width.

What a santoku is for

A santoku is a general-purpose kitchen knife from Japan, used at home on meat, fish and vegetables. The name is written 三徳 and is usually translated as "three virtues" or "three uses". The Sakai knife company Ichimonji gives the usual blade length as 165 to 180 mm (about 6 1/2 to 7 in). It also mentions mini santokus of 145 to 150 mm, so the 6 3/4 in preset sits in the middle. The blade is tall and the edge nearly straight, with a gentle curve toward the tip. Ichimonji says a straight edge leaves less of a gap against the board, so less food is left uncut. The trade-off is rocking. Wikipedia notes that the straighter edge allows only limited rocking, so a santoku relies more on a single downward cut. Most of the santokus ATK tested had a gently curved edge that allows a slight rock. The bunka (bunka bōchō) is a close relative with a straighter, more angular tip, and the two names are often used for the same knife.

Most santokus have a sheep's foot tip, with the spine curving down to meet the edge. ATK calls it the santoku's most recognizable feature but says it is simply meant to make the knife look less intimidating. ATK adds that it puts more metal behind the tip than a typical chef's knife has. In ATK's testing it was more of a problem than a perk, because testers had to push harder for delicate vertical cuts through onions. Many Western versions of the santoku also have a row of oval hollows ground into the sides near the edge, sold as a Granton edge or a Kullenschliff. The hollows are meant to stop food sticking. ATK's testers didn't notice any less sticking on the seven blades that had them, and two of the top three had none. ATK's view is that on a slicing knife they cut friction, while a santoku is already short and thin enough not to need them. The Granton edge comes from Sheffield: in a 1947 trade fair listing, William Grant & Sons called themselves the sole makers and patentees of the "Granton" edge. William Grant's US patent 1,793,171 (issued in 1931) covers a blade with a series of depressions next to the cutting edge. If you want them, leave the blade thick enough. Wikipedia notes that hollows need a certain blade thickness, so they turn up more on thicker, softer blades.

None of the origin story is confirmed, so take it as story rather than history. Japanese knife makers tell it in much the same way. Tojiro says the bunka was developed in the Shōwa era (1926 to 1989). It joined the good points of the gyuto and the nakiri (the rectangular vegetable knife), with the tip cut off at an angle. Rounding that tip, Tojiro says, gave the santoku. Ichimonji's English site has the santoku growing out of the nakiri, the deba (a fish knife) and the bunka. The English and Japanese Wikipedia articles both put it in the 1940s and count the deba among its parents. Ichimonji's English site, Knifewear and some other Western retailers date it to the 1940s, and some tie it to the years after World War II. None of these histories names a designer. Which three virtues the name means is unsettled too. Ichimonji's Japanese site and the Japanese Wikipedia article give meat, fish and vegetables. Ichimonji's English site and English Wikipedia also give a second reading, the cuts (chopping, slicing and dicing), and some Western retailers give only the cuts. Even the hollows have a muddled date. Wikipedia dates the Granton patent to 1928, and Bernal Cutlery says the Granton and the Kullenschliff were both patented in the UK that year. But William Grant's US patent cites a British application from February 1929.

Stock for a santoku

In a BladeForums thread on santoku thickness, one poster puts a short, light blade at 0.06 to 0.10 in and heavier, longer blades at 0.10 to 0.15 in. Another makes santokus from 1/8 in stock that finish around 0.100 to 0.110 in. At the thin end, a maker who says he has made a lot of santokus describes one in 0.075 in AEB-L at 63 HRC, ground full flat to zero.

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.

Steels that suit it

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