Challen started to make the largest piano in the world for the Silver Jubilee of George and Mary, in 1935. There may have been two pianos or the one withdrawn repainted and polished and turned out again. There was a letter in the Piano Tuners Quarterly form Challen dated 19th December 1940, saying:

"Particulars of the world's largest grand piano, manufactured by Charles H. Challen & Sons. This instrument was made in honour of the Silver Jubilee of their Majesties King George V and Queen Mary and is the largest grand piano in the world. It has created a profound impression in musical and engineering circles. It is eleven feet and eight inches long, weighs one and a quarter tons, and the combined tensile stress of the strings amounts to over thiry tons. The iron frame alone weighs six and a half hundred weight and the longest bass string is nine feet eleven inches.

The experimental work in connection with its production took over twelve months, and the cost amounted to over £600. In spite of its immense dimensions and strength, so perfectly has everything been calculated that it is even easier to play than an ordinary piano. It is a feat of British piano engineering, which places the British industry definitely on top. It was first shown at the British Industries fair in 1935, where it was inspected by H. M. the Queen, and was played for her by Billy Mayerl. At a later date Sir Walford Davies, Master of the King's Music, also played the instrument and in reference to the piano he stated 'it is indeed a glorious instrument. It has the bass of an organ and yet the intimacy of touch and tone of the finest piano I have ever played. A great achievement'. It has been used on several occasions for broadcasting."

--Charles H. Challen

1934

Alfred Knight started his own piano building business.

1934

Brasstead introduced the Swedish designed minipiano which had its wrest plank below the keyboard, a drop action and double-ended wrest pin holding bichords throughout. Later Jack Davidson Brasstead introduced a flanged frame to which the case work was fixed and the more traditional design came into the Minipianos.

1935

Steinway patented the capo d'astro bar which is part of the iron frame and forms the top bridge in the treble. Other makers had used it for the whole compass of the piano instead of studs in the bass and middle sections. It improves the tone and gives more clearance for the hammers as the bar bears down, whereas studs are fastened from below and worn hammers can catch on these and break on removal of the action. The fall on a Steinway is usually pinned to the key blocks similarly to Erards of the same period in the nineteenth century.

1936

The BBC held a grand piano test in 1936, which included three categories, according to length. Bösendorfer won the largest and smallest size, and Challen and Steinway shared the 7'6" to 9'.

1938

Chappell bought Johann Strohmenger & Sons.

1939

An English patent was awarded to Alan Blumlein for his invention of stereo. He was killed in a plane crash in 1942.

1948

Ajello & Sons of Manchester was formed. They were related to Ajello of London and made pianos from 1948 to 1960. You find a lot of these small over-strung pianos in the north of England.

1948

The Swedish firm Lindna introduced plastic parts, about which the less said the better.

1953

The Paris branch of Herrburger Brooks closed.

1956

Pearl River Pianos was established. They started with six shops and a workshop, and now have a work force over 4,000 and over 300,000 square meters of factory floor space. Production of pianos is 100,000 per year. Twenty percent of their production is exported to the west.

1956

Kawai was now employing over 500 people and producing just over 1500 pianos per year. Koichi Kawai received the prestigious "Blue Ribbon Medal" from the Emperor of Japan, becoming the first company in the Japanese musical instrument industry to receive it. Koichi Kawai died suddenly in October of 1955 at the age of 70. Around this time 33-year-old Shigeru Kawai took over the company and embarked on radical changes. He began construction of two new factories, one a wood processing plant and the other a piano assembly plant, becoming the company's first modern production line.