In Chigorin and Schiffers, I quoted from the 1895 Hastings tournament book:
[Chigorin's] style of play is quite of 'the old school', brilliantly attacking and ever towards the King, perhaps best described by the simple word beautiful. He is probably the greatest master of the King's side attack and rarely plays dull games. His chief energy is thrown into the middle game rather than the opening, which he sometimes conducts with too much indifference. His analytical ability is of the very highest order, and blindfold play does not come amiss.
In Chigorin and His Contemporaries, I quoted from Kotov & Yudovich's Soviet School of Chess:
Tarrasch and the masters and critics who supported him claimed that they had formed a 'modern school', while Chigorin represented out-dated views, i.e. the old school. Steinitz and Tarrasch failed to understand the essence of creative thinking in chess, which they tried to subordinate to abstract and unreasonable principles. It is clear today that their views were erroneous and narrowed down the rich content of chess. [...] The Russian champion's creative imagination, his critical attitude towards the pronouncements of recognized authorities, his quest of the new, and, finally, his deep faith in the limitless creative possibilities of chess made his investigations a major contribution to theory.
The Soviet authors went on to give dozens of examples showing Chigorin's contribution to opening theory. In the 19th century, Chigorin was considered 'old school' and sometimes indifferent to the openings. In the mid-20th century, he was considered the forerunner of the Soviet School (the antithesis of 'old school') and a major contributor to opening theory. How to explain those opposing points of view?
I take it as a given that Kotov & Yudovich were right, while the end-19th century pundits were wrong. After all, chess theory progressed substantially during the ~60 years following Hastings 1895, and accelerated under the scrutiny of the Soviet grandmasters. Following is a graphical overview of Chigorin's openings at Hastings 1895. This is what his contemporaries 'saw' of his style.
The picture squares with the overview of Chigorin's theoretical contributions as laid out in Soviet School: Evans Gambit (as both White and Black), Two Knights Defense (Black), King's Gambit (White), and the unusual 2.Qe2 reaction to the French Defense (White). It doesn't show the ...Nc6 defense to the Queen's Gambit, but the notes to the Hastings 1895 games show that he was already recognized for that system.