I play this every year with my first graders and they always have a blast. This is a race done in rows so the only thing you`ll need to prepare beforehand is 1 dictionary per row and either 1 paper or 1 whiteboard and marker per row. The powerpoint I uploaded will have enough words for three races but if you want to add more races or change the words around, just do it beforehand! All english/japanese dictionaries are different so please make sure the dictionaries your school has, has the words they'll be looking up.
The way the race is played is the first person in each row looks up the first word and writes the japanese definition down. They then pass it to the person behind them and then the second person will look up the second word. This will continue until all the words have been looked up. When a row finishes, they need to run up to you and show you their paper/whiteboard and you need to check it. I know all of the words in Japanese and have memorized the kanji for this activity but majority of people will need to either memorize the definitions OR just keep the answers on a sheet so you can check it. I give the first three rows a prize.
Looking up definitions will be doable for most BUT there will be some students who really struggle. So what I've done is made it so that the person sitting directly behind the person looking up the word can help! However, they MUST do this with their hands behind their backs. If not, many of the students will end up just looking it up for the other person. When it gets to the last person in the row, the first person will run to the back and help them. Adding this helper rule actually ended up making it a lot more exciting and the kids loved it.
Some final notes:
I have had cases where the person looking up the word, and the person helping were having a hard time. I normally wait until they are the last person still on a word before I try to help them. Use your better judgement when it comes to helping students when they are stuck. I added a slide reminding kids to use the guide words at the top of the page. Many kids looked at the main letter and just tried to magically find it without looking at the guide words. Sometimes, you will also have a row that has very few people in it due to absences or something. I like to ask my JTE to join. The students get hype when its time for their teacher to look up a word. If its a quiet row, my teacher becomes very 大人げない and will try hard to win stickers for all of them haha. I`ve never NOT had fun doing this activity and if you don't do this already, please give it a try!