Shun knife sets are made using two traditional styles of Japanese knifemaking. The first style- the kasumi style- is the style used to make knives that are found in The Shun Classic Sets such as the Shun 9 piece block set and the Shun 7 piece block set .
The Kasumi style of knifemaking is the same style that has been used for centuries in Japan as the art of making samuri swords. It uses an extremely high quality, high carbon steel for the core which is covered by up to as many as 16 coats of a softer steel. 16 coats on each side. These coats of steel protect the inner core and when the knife is finely sharpened it is the inner core that produces the edge. In Japanese the word Kasumi actually means mist this traditional way of knifemaking is called Kasumi because of the misty appearance that the outer shell of the blade has after the layers of steel have been added. If you are interested more in knives that have been made using this technique have a look at The Shun knife sets that are reviewed here.
The Honyaku method is a slightly different style. In the Kasumi method knives are made with an inner core and multiple softer layers are applied to the outside to keep the inner core strong the Honyaku method of knifemaking uses only one single high carbon piece of steel this piece of steel produces a knife with a super fine edge that lasts for a very long time whilst in continual use. As you can imagine these knives take much longer to make than knives that are made using the Kasumi method and therefore they cost a lot more and are seen as the very best in kitchen utensils. The Shun Pro lines features knives that are made using this style.
Have a look at some reviews for the Shun knife sets that feature the Honyaku method of knifemaking.