Is it Permissible to Play with Lego on Shabbat?

Greetings,

It is permitted for children to play with Lego on Shabbat, as this is analogous to what is stated in the Shulchan Aruch (Orach Chaim 306:6) regarding a cup of pieces, which may be taken apart and put back together on Shabbat, because there is no building and tearing down with utensils. The same applies to Lego, as the structures created with it are not permanent at all, and they are not connected by screws or nails, and they are meant to come apart at any moment; therefore, there is no issue of building and tearing down at all (Responsa Yechave Da'at, Part 2, Section 55).

However, children who have reached the age of education should be warned not to build a structure like a house or any other space that has a roof and dimensions of a tefach by tefach (approximately 3.5 inches by 3.5 inches) and a height of a tefach beneath it, if they use the airspace for placing objects or toys, due to the prohibition of making a tent. And if they do so, it is prohibited to dismantle this "tent" (Aruchot Shabbat, Part 1, Chapter 9, Section 13).

After the age of bar mitzvah, it seems from the words of Rabbi Ovadia Yosef, zt"l, in the aforementioned Responsa Yechave Da'at, one should certainly refrain from playing with Lego on Shabbat. Nevertheless, he wrote in his book, Responsa Yabia Omer, Part 7 (Orach Chaim 40:4), that it is permissible for an adult to allow a child to play with toys specifically meant for children, as they do not fall into the category of muktzeh (items that cannot be moved on Shabbat).

Shabbat Shalom,

Hillel Meirs