While the majority of his work for the last thirty years has been in graphic identity, environmental graphics, and product design, his exploration and experimentation with letterform and isometric grids has brought him international attention and recognition. In the early 1980s, his two-dimensional, isometric alphabets, firstconceived as a series of poster calendars for the Museum of Modern Art in New York City, quickly evolved into three-dimension-al alphabetic structures that Igarashi called architectural alphabets.

The Aluminum Alphabet Series, the first to involve typographic sculptures, comprises twenty-six three-dimensional, aluminum letterforms. Each sculptural form consists of a series of aluminum plates of varying thickness joined together by flat-head aluminum fasteners. Here, Igarashi uses letterform to explore the potential of three-dimensional form. He says, "One of the charms of the Roman letter is its simple form. The wonderful thing is that it is created with the minimum number of elements; the standard structure is based on the circle, square, and triangle, which are the fundamentals of formation."

Letterforms are basically symbols or signs written on paper in a flat, two-dimensional world. Design of letterforms can be varied by extending their two-dimensional characteristics into a three-dimensional world. Letterforms can also be considered as simple graphic compositions of basic geometric elements—circles, squares, and triangles—and within these compositions are hidden possibilities for developing a greater set of shapes and forms.

Igarashi's approach for this series was to conceive letterforms as solid volumes divided into positive and negative spaces. A three-dimensional composition is realized when the form of the letter is extended in both its positive and negative directions; in other words, by generating spatial tensions in both directions. He states, "This is one example of my attempt to find a geometric solution between meaning and aesthetic form. Based on a 5-millimeter [1/4 inch] three-dimensional grid system, the twenty-six letters of the alphabet from A to Z were created by adding and subtracting on the x-, y-, and z-axes."

The Aluminum Alphabet Series is a unique, groundbreaking result of taking a conceptual, spatial, and mathematical view of letterforms and revealing some of the many possibilities of shape and form. It is the ultimate study in letterform, material, detailing, visual interpretation, and three-dimensional form.