Japan — kabayaki unagi preparation documented from Edo period; the tsume reduction technique integral to Edo-mae sushi tradition; teriyaki as a glaze concept developed alongside the yakimono tradition; Narita and Naritasan Shinshoji temple area famous for unagi kabayaki
Tsume (詰め, 'reduced/concentrated') refers to the specific reduction sauces used to glaze grilled fish and seafood in Japanese cuisine — most famously the thick, sweet-savoury glaze applied to unagi (freshwater eel) and anago (saltwater eel) in traditional Edo-mae sushi and kabayaki preparations. The tsume for unagi is produced by simmering the eel's head and bones with soy sauce, sake, mirin, and sugar until the liquid reduces to a thick, glossy syrup that coats the back of a spoon heavily. This bone-based reduction contains gelatine from the eel's connective tissue, which gives it body and gloss that a simple soy-mirin reduction cannot achieve. Different from teriyaki glaze, tsume is applied multiple times during grilling in the kabayaki method — alternating between steam-cooking (mushiyaki) and direct charcoal grilling while painting tsume in successive coats that build up a lacquered, caramelised exterior. Anago tsume differs slightly from unagi tsume in its seasoning balance — anago's more delicate flesh requires a less assertive glaze. The teriyaki glaze concept is broader: equal parts soy, mirin, sake reduced with sugar to a coating consistency, applied to fish (buri, yellowtail being the classic), chicken, or beef in the final minutes of cooking. The Japanese teriyaki differs from Western interpretations in being lighter, less sweet, and applied only in the final 2-3 minutes of cooking rather than throughout.
Unagi tsume: concentrated eel gelatine sweetness with soy-mirin caramelisation; builds in intensity with each coat; creates the characteristic thick, almost candied surface of kabayaki eel; teriyaki glaze: brighter, lighter than tsume; caramelised soy-mirin with clean, sweet finish
{"Tsume for eel: head and bone-based reduction creates gelatine body and depth impossible with boneless versions","Multiple coats: tsume applied in 3-4 thin coats during grilling builds lacquered surface; each coat caramelises","Kabayaki technique: alternating steam (mushi) and grill (yaki) with tsume application at each grill phase","Teriyaki late application: add glaze only in final 2-3 minutes — earlier application burns and creates bitter residue","Soy-mirin-sake ratio for teriyaki: 1:1:1 as base, adjust sugar to desired sweetness level","Anago vs unagi tsume: anago requires lighter glaze; unagi tsume is more concentrated and assertive"}
{"Unagi tsume starter: roast eel bones and head at 200°C until fragrant; simmer with soy-mirin-sake for 30 minutes; strain and reduce","Glaze brush technique: use a wide pastry brush; apply in thin uniform strokes; allow to caramelise 30 seconds before reapplying","Teriyaki buri (yellowtail): the high fat content of buri makes it ideal for teriyaki — fat prevents drying during repeated glazing","Tsume storage: refrigerated tsume keeps weeks; reheat gently before use to restore fluidity","Anago tsume finishing: thinner and lighter than unagi tsume; the final coat should leave a sheen, not a thick lacquer"}
{"Over-reducing tsume — too thick cannot coat evenly; should flow slowly from a tilted spoon","Applying teriyaki glaze from the beginning of cooking — burns, creates bitter compounds","Skipping the bone-reduction step for unagi tsume — uses only soy-mirin; lacks the gelatine body","Reusing tsume that has been contaminated by direct contact with raw fish — cross-contamination risk","Applying glaze with too heavy a brush stroke — thick uneven application causes uneven caramelisation"}
Tsuji Culinary Institute — Japanese Sauce Reductions and Glaze Techniques