Clay Payne started the game for Bloomfield but didn't make it out of the first inning.
"We had a rough first inning and Miyamura swung the bat well," said Bloomfield head coach Frank DeHoyos.
Miyamura and Bloomfield are both looking for a spot in the state tournament, and DeHoyos knows Thursday's loss could be costly.
"It was important for us to show better than we did in this game, and I am afraid it might bite us later," he said. "We have to beat Aztec and we have to play really well against Farmington now. I hope we took care of business by finishing third in this district, but seeding committees see something different sometimes."
Bloomfield is now 9-11 overall with a 3-3 District 1-4A-record, but DeHoyos hopes the NMAA will consider close losses to Hope Christian and St. Mike's, two of the top 3A teams, as positives rather than a 4A team losing to a 3A team.