Rubik's Cube owner Spin Master Toys UK on Wednesday lost its battle against a Greek rival as Europe's second-highest court annulled trade marks related to the shape of the iconic puzzle.

Invented by Hungarian professor Erno Rubik in 1974, the multi-coloured cube puzzle is popular among young and old, with hundreds of millions sold worldwide. The brand was acquired by Canadian children's entertainment company Spin Master in 2021.

Spin Master took its case to the Luxembourg-based General Court after Greece's Verdes Innovations SA in 2013 asked the EU trademark office to invalidate several trade marks registered by Spin Master's predecessor between 2008 and 2012.

The European Union Intellectual Property Office (EUIPO) backed Verdes, saying Spin Master Toys trade marks had been registered contrary to EU law. The Greek company makes puzzle cubes under the V-CUBE brand.

Luxembourg-based General Court backed EUIPO.

"The General Court confirms the annulment of trademarks consisting of the shape of the 'Rubik's cube'," judges said.

"As the essential characteristics of that shape are necessary to obtain a technical result, it should not have been registered as an EU trade mark," they said.

Spin Master Toys, which can appeal to the Court of Justice of the European Union, Europe's highest court, did not immediately reply to an emailed request for comment.